I must have approximately twenty different models of KZ in-ear monitors (IEMs). This ZST is Knowledge Zenith's first venture into hybrid (dynamic driver + balanced armature) territory and in my humble opinion this is an excellent IEM.I tend to prefer a relatively neutral sound signature with a slight emphasis in both bass and treble, which is basically a mild "V" shaped sound signature. I find that an absolute neutral sound signature usually lacks enough energy for the genres I enjoy most, which are Classic Trance and Progressive (early Tiesto, Markus Schulz, Otello, DT8 Project), Chill Out, Breakbeat (Hybrid & Burufunk Remixes) and 80's & 90's (New Order, Secession, The Cure, Siouxie & The Banshees, Depeche Mode). Sure I listen to Shania Twain, Sade, Bach, Ella Fitzgerald and everything in between, but as of late the bulk of my listening pleasure is focused on the aforementioned genres.Take note when you read IEM reviews that when the reviewer gives his/her opinion regarding the sound that there are many factors that shape the final sound an IEM delivers to one's ear.Those factors include:1 - Shape and size of the reviewer's ear canals. (shallow or deep, wide or narrow)2 - Shape and size of the eartips [round or cone, single, double or triple flange] & proper fit3 - Materials of the eartips (silicone/foam)4 - Shape of the IEM (and/or angle of the nozzle) can cause fitment issues for some.5 - Source (quality of smartphone, laptop, digital audio player) is amplified/unamplified.6 - The IEM itself (driver flex possible due to trapping air in canal causing muffled sound.7 - The Reviewers ability to hear all frequency ranges (age plays a factor).Most consumers are unaware of how much weight each of these factors hold in rendering a final verdict. This is why there is such a wide variance in not only ratings, but the description of an IEMs sound. An unaware consumer purchases a perfectly fine IEM but has difficulty keeping the IEM in the ear or he/she does not satisfactorily seal the ear canal with the included silicone eartips (this has happened to me on numerous occasions) and summarily dismisses the IEM as sub par. Another consumer purchases the same IEM but experiences a perfect fit and seal and has nothing but praise for the same IEM. Sealing the ear canals AND HAVING THE EARTIP FIRMLY AFFIXED to the IEM nozzle when using IEMs is the determining factor to render a valid verdict. I can think of no audio equipment that is subjected to such praise or ridicule as the in-ear monitor. As if that's not enough, there is no "one-size-fits-all" when it comes to IEM eartips.Materials (silicone or foam) have different damping effects on the final sound.The shape of the eartips (olive-shaped, cone-shaped or other-shaped) can have different damping effects on the final sound based on how much space is between the IEM nozzle and your eardrum and how well the eartip has sealed the ear canal.The aperture of the eartip's opening (wide-bore or narrow-bore) will have damping effects on the final sound.The easiest way for you to experience the different effects I am discussing is to take your current on-ear earphones or over-ear earphones, pick a song full of energy, put the earphones on and let them sit naturally over/on your ears. Listen to them for two minutes. After two minutes, using your hands, slightly press the headphones closer to your eardrums. Notice the change in the sound. Is there more/less bass? Is there more/less treble? Did the vocals slightly slip forward/back?Consider that on-ear and over-ear headphones have a driver that sits approximately 1 1/2 inches to 2 inches from your eardrums and by pressing the headphones 1/4" closer to your eardrums the sound changed. Now consider that an IEM sits anywhere from 3/4" to 1/4" from your eardrums and the slightest changes (angle, depth, shape, material) can have up to three times more of an effect due to the proximity of the IEM to the eardrum.For this reason, I think it is wise to invest a nominal dollar amount on different eartips to get everything the earphone tuners intended. Personally, I think anything less is folly. Some IEM manufacturers supply multiple sizes (S,M & L) and materials (silicone & foam) of eartips to increase the odds that the consumer achieves a satisfactory seal, but even this is not foolproof. If this holds any interest for you some aftermarket brands to look into are "JVC Spiral Dots", "Spinfits", "Comply Foam Eartips" or "Znari Foam Eartips", "Creative Aurvana" and others.The Knowledge Zenith ZST:First thing is first. Knowledge Zenith currently has four lines of in-ear monitors, each offering a specific sound signature:AT series:----Lush mid-centered over-ear IEMs(ATE, ATE-S & ATR)ED series:------Variations of mainstream neutral tuning to "V" and "W" shaped tuning IEMs.(ED1, EDSE, ED3 'Perfection'&'Acme', ED4, ED7, ED8, ED9, ED10, ED11, ED12, EDR1, EDR2).HD series:---Micro-dynamic driver IEMs (one of my favorites)(HDS1, HDS2, HDS3 & HD9)ZS series:------Bass forward over-ear IEMs.(ZS1, ZS2, ZS3 & ZST)Be aware that the ZST is in the "ZS" model lineup and are therefore bass-forward or bass oriented in-ear monitors. If you'd like something more neutral (HD line) or lush (AT line) check out any of my reviews by clicking my name at the head of this review to get a better description of each in-ear monitor that would cater more to your preferences.Knowledge Zenith has been progressing quite nicely with high quality dynamic driver IEMs for the most reasonable prices in the marketplace today. Indeed, the marketplace is awash with inexpensive decent sounding in-ear monitors (from Asia), but KZ seems to be stealthily pulling ahead to become the proper example for how to do things right. If you've never sampled the KZ ED9 ($12.99), KZ HDS1 ($8), KZ ED10 ($10) or KZ ATR ($8) then do yourself a favor and treat yourself because nothing in the sub-$20 category at Wal-Mart, BestBuy or Fry's Electronics will come close to what KZ offers. Maybe even sub-$50.Personally, I am still so thoroughly enamored with the new KZ ZS3 that I think that Knowledge Zenith would have to pull a rabbit out of its hat in order to outperform the ZS3. Not that the ZS3 is the "end all" or "be all" IEM. It's just that its level of imaging, presentation and overall coherency were never even remotely offered for LESS THAN $20 (at the time of its release). Let that sink in.....LESS THAN $20!At any rate, I don't think outperforming the ZS3 is KZ's purpose in offering the new ZST.....YET! That will likely happen when KZ issues a 2 balanced armature (BA) + 1 direct driver (DD) "ZS" series IEM. I would bet dollars to doughnuts that this will happen.At first glance, the timing of the release of the ZST may seem questionable because it is directly on the heels of the newly released and highly acclaimed ZS3 (approximately 10 weeks separate the release dates), but I don't think there could be a better time for KZ to introduce their venture into the world of hybrid in-ear monitors.Why?Hybrid monitors can be a very tricky proposition mainly due to the use of two completely different technologies. A direct driver produces sound by the movement of air via a diaphragm and voice coil. The movement of air is why direct driver IEMs typically have a small vent or hole in the driver housing. A balanced armature produces sound via a resonating coil suspended between two magnets (changes in electrical current cause attraction between the coil and magnets) so there is very little movement of air which is why BA in-Ear monitors typically have no vents and offer better isolation. Different technologies. Different results. A balanced armature driver/receiver responds faster to audio input and produces a more detailed sound, usually performing at their best in a specific frequency range which is why many balanced armature IEMs contain multiple receivers. However, balanced armature drivers lack the unadulterated power (rumble and punch) of the bass that dynamic drivers produce. A properly tuned dynamic driver (like the KZ ZS3) can sometimes offer a more coherent sound across the entire frequency range though it will lack the detail and micro-detail produced in a balanced armature.When one comes to understand balanced armature technology and direct driver technology it becomes evident that successfully coupling a "single" BA (for highs & mids) with a DD (for lower frequencies), at the time of this review, has be very tricky for some manufacturers. Get it wrong and the overall presentation may come across as incoherent (Sony XBA-H1). This is a result of the DD delivering a full bodied sound versus the BA delivering a thinner but highly resolute sound. The thing is, if you get it right your clients and peers will hold you in high regard.Walking this tightrope is why I think this is the best time for KZ to release the ZST. Knowledge Zenith has two well priced IEMs (KZ ZS3 & KZ ATR) that have the hobbyists abuzz and astounded at their price to performance ratio. Releasing the ZST now ensures that if the ZST gets a lukewarm reception the way Sony's XBA-H1 (Sony's first attempt at a hybrid offering) did, then the hobbyists would still have an excellent array of KZ IEMs to fall back on. Funny thing is Knowledge Zenith does not have the same resources that Sony has, but apparently, KZ succeeded where Sony did not, although you could argue that KZ is standing on the shoulders of a giant. Do the research and find out how many XBA-H1's (originally priced at $200) have been returned and subsequently sold as refurbished (at a staggering 85% discount - $30). I don't think the ZST will have that problem as long as those of you purchasing the ZST couple it to a sufficiently powered source. Balanced armature IEMs will sound there best when paired with a sufficiently powered source,. With BA's, a power EFFICIENT source (smartphones or DAPs with 20+ hours of playback) will likely present a rather bright sound signature that may induce fatigue for the listener.In my opinion, Knowledge Zenith had to be very wise in their approach to offering a coherent sound signature with "just one" BA in order for the ZST to be a success. Which lower frequencies should the DD bracket? Which frequencies should the BA bracket, given its narrow but focused capabilities? Enough, with the rhetoric. Let's take a look at what KZ has offered with the new ZST.The initial release (first batch) of the ZST suffered from an incomprehensible flaw: The balanced armatures were not firing. This means that all that was being presented was the Dynamic Driver's capabilities which was a gradual decreasing slope from 30hz to about 6,000hz+/-. This gave the intial batch a warm presentation because the BA's failed, and no high resolution detail in either the mids or treble region was to be found. This is conjecture on my part but I'm pretty sure this was the case. How did I come to this conclusion? I have several pairs of ZST's, including the intial batch ZST. My second pair of ZST's were perfect until I spent most of the day (12 hrs) with them and later fell asleep with them in my ears. The next day I fired them up and the BA failed within five minutes. They sounded just like the initial batch. I took them out of my ears and set them aside for 8 hours. When I plugged them back in, the BA's were back to normal, but again only for about five minutes. I think either ear wax or moisture has effected the BA's moving arm. This was a heartbreaking occurrence because the ZST, when sufficiently powered, can go head to head with some fairly expensive gear. Fortunately, I have a third pair of ZST's which I WILL NOT SLEEP WITH IN EAR, and yes, now I will be ordering two more pair as backups, 1 Carbon & 1 Colorful.I think KZ should move the BA back about half an inch more from the nozzle entry. Right now, it's literally right at the nozzle entry. Let's hope Knowledge Zenith is listening and does make the necessary adjustments for an easy fix to a simple dilemma. I've ordered every model that KZ has released in the last year and I've become familiar with how they respond to customer input by further refining their offering once consumers have real life experiences with the product that KZ has released into the marketplace. Personally, I admire their dedication to 'getting it right' if there is room for improvement rather than just shrugging their shoulders the way many larger companies seem to do.I tested the ZST with Knowledge Zenith's new "Silver Plated Upgrade Cables" and the stock cables. Rather than lengthen this review with the differences in sound, please see my review on the upgraded cables by clicking on my name and scrolling to the ZST 2-pin upgrade cable, but be aware that the ZST sounds fantastic with the stock cable. Still, it's more to my liking with the upgraded cables.The ZST sounds ALMOST like two different IEMs, depending on which source I use. There was a definite difference in sound between the more powerful Fiio X3i and the less powerful ZuneHD. The ZuneHD, which is power efficient, allowing 25+ hours of playback, sounded fine but lacked the body or punch in the low end that the Fiio delivered. Through my ZuneHD the ZST sounds more analytical because the low end is somewhat neutralized resulting in a bright leaning sound signature, but the ZST just came alive when it was coupled to the more powerful Fiio X3i. Everything below 100hz had more body and heft which perfectly complimented the smooth detailed energy the BA put forth. A power efficient DAP, especially if it has a higher output impedance will not pair well with the ZST. Please check the output impedance if your device before ordering. A poor match with your device means the ZST will sound off-putting (bass-shy, shouty mids or strident treble).Test tracks were the following:Ella Fitzgerald & Louis Armstrong - "Gee Baby, Ain't I Good To You"Ella Fitzgerald & Louis Armstrong - "Learnin' The Blues" (test shouty mids on trumpet)Diana Krall - "Maybe, You'll BeThere" (sibilance test on 'Ssss')Diana Krall - "Baby, All The Time"Van Halen - "Hot For Teacher" (test of busy drum intro)Metallica - "Nothing Else Matters"Dream Theater - "Pull Me Under" (test for body, crunch and micro-detail)Tourniquet - "The Hand Trembler" (coherency in a busy and layered performance)Shania Twain - "No one needs to know"Tim McGraw - "She Was Mine For A Little While"Tears for Fears - "Woman In Chains" (test for Clean bass and mids w/ Oleta Adams)Morcheeba - "Blindfold" (test for clean bass)Massive Attack - "Teardrop" (test for Clean bass & guitar presentation)Portishead - "Roads" (test for vocals and note holding texture on keyboards)Schiller - "Under My Skin" (test clean bass, vocal presentation and micro-details)Beth Orton - "Central Reservation"Beth Orton - "Daybreaker"Jackson 5 - "I Want You Back" (test for imaging and separation)Secession - "Magician (Pecky Plus Mix)" (male vocals/lower mids vs upper bass)The Church - "Under The Milky Way" (test for acoustic guitar presentation)Otello - "Masterworks Collection: Rabbit Hole" (test handling complex bass & drums)Otello - "Masterworks Collection: Las Vegas" (test handling complex bass & drums)Otello - "Masterworks Collection: Downtime" (test clean bass & vocal presentation)Antonio Vivaldi - "L'Estro Armonico" Violin Concerti (test for shouty mids/violins)Sound Signature:1) The ZST is a detail oriented in-ear monitor. These definitely lean more toward analytical, though they are not neutral. The micro- details are displayed in full and the detail from as low as 30hz all the way up to 20,000hz is excellent.2) The ZST is a full spectrum in-ear monitor. The bass digs down deep and highs are clean, displaying ZERO sibilance. With modern genres like Trance, Progressive House, Drum & Bass, Chill Out and various EDM genres the ZST sounds incredibly full. These have an energetic "W" sound signature.Here's the breakdown:(Be aware: I do not use the included Star-tipped eartips on the ZST. The eartips in the photos are pulled from my Rock Zircon IEMs and they balance the bass/treble ratio to perfection for my ears.)Bass: It's all about delivering full but controlled bass and it behaves better than I expected in tracks that don't call for boss bass. This was probably the biggest surprise for me given how authoritative the bass is delivered in modern genres. I'm not a basshead, per se, but I really enjoy the thunder these produce when it's called for and how punchy and clean it comes across on a wide variety of genres. Instead of the bass just dominating the whole scene, it seems to just lock arms with the other instruments on stage and just sway......in rhythm......in joy......in the moment and it's magnificent for $18. KZ tuned these so the beautiful bass doesn't bleed into any other frequencies. That means the lions share of the work is done by the BA. That sounds like such an obvious explanation, but many big name manufacturers still haven't successfully tuned a simple 1BA+1DD IEM the way KZ has (Xiaomi Hybrid). We'll done KZ!Mids: Centered with admirable texture on female vocals. Male vocals and lower mids would benefit from a bit more warmth, but I'm not complaining. As far as I am concerned, for $20, your trade-off is sacrificing lower mid-range warmth whilst avoiding mid-bass bleed. I'll take it, thank you very much. Mid-bass bloat has ruined many otherwise excellent IEMs and trying to tame mid-bass via tip-rolling is tricky.Highs: Crystal clear with smooth micro-detail. Zero sibilance! The big test for me is always Diana Krall's "Maybe you'll be there" and the ZST passed with flying colors. Not a single wince! Again, be aware that the output impedance of your source WILL determine how clean the BA in your ZST will sound. This is why I recommend the ZST be coupled with a sufficiently powered source. If your only source is a smartphone or power efficient (20+ hours of playback) DAP and you really want the ZST, then pick up an amplifier (Fiio A3 or Q1 or equivalent). Personally, I don't think you should be looking at balanced armature IEMs if your primary source is a smartphone, but apparently some smartphone manufacturers seem to be addressing the quality of the DAC's (digital audio converter) in their phones so you'll have to do your own research on which manufacturers models are capable of handling the demands of a balanced armature IEM.Soundstage and Imaging: The Soundstage has slightly above average width. The whole presentation is displayed as though the instruments are on stage at an intimate venue as opposed to a wide stage at a grander venue. The space between the instruments makes it easy to pinpoint their placement but it is as if the instruments are placed several feet from each other, so the presentation leans more toward intimate as opposed to airy and spacious. My Rock Zircon eartips (below) may have narrowed the width on the soundstage, so take that into consideration.As I am writing this I am listening to "Blindfold" by Morcheeba. The bass line is so clean and the drums have an excellent kick and heft to them. Love these things.Bottom line is this:THE ZST IS EXCELLENT ON A SUFFICIENTLY POWERED SOURCE!If you plan on hooking these up to your phone or an efficient DAP (20+ hrs of playback time) chances are you'll miss out on the best that these have to offer. You'll miss the fullness and rumble in the low end which is the whole point of the DD in this hybrid. In addition, be aware that you will get ever so slightly more low end grunt with the stock cables if that's your preference.THE ZST WILL BE MERCILESS ON POORLY RECORDED MATERIAL.Mediocre files will indeed sound......mediocre. High quality recordings will sound unreal for a sub-$20 IEM. But take note, you can listen to '256kbps mp3' material and even '192kbps wma' formatted material with confidence so long as the recording itself is of high quality.In my humble opinion, as I am writing this review, the ZST trumps everything that preceded it in KZ's distinguished sub-$20 IEM lineup with the only exception being the ZS3. To my ears, the ZS3 and the ZST are tied for best Knowledge Zenith offering. They are two completely different presentations. The ZS3 brings an organic lifelike and full bodied presentation to the table, whereas the ZST brings a technically forward up close and personal presentation. Both are magnificent for IEMs that retail for under $20.Yes, these trump the ATR. There is no contest! The ZST is not one, but two tiers above it in presentation alone. Those are fighting words because the ATR (at $8) is an excellent IEM but it's true. I've gone back three times to double check and there is no contest as far as I am concerned. I finally asked myself why I keep double checking when the answer is so profoundly clear.THE ZST IS JUST BETTER, primarily because the BA delivers cleaner, faster, more resolute mids and highs than the ATR's single dynamic driver is capable of. Listen to the ZST for an hour or two uninterrupted, then swap to the ATR and you may want to remove them immediately, as I did. The drop in resolution in the higher frequencies is quite jarring. You'd never notice it without a back to back comparison, but once you notice it....it's hard to ignore.Reminds me of the old adage "How do you un-ring a bell? .........You can't!"I enjoy the ATR. I enjoy the ED7 (standard size) more than the ATR, but this ZST makes it hard to justify going backwards, as good as both the ATR and ED7 sound. I will try to squeeze in some time for the ED7 because I really enjoy them, but that may be wishful thinking on my part because the new ZST's resolution sets a new standard for me.The ZST is indeed an upgrade and improvement over EVERYTHING Knowledge Zenith has offered to date.No other KZ has the resolution (mids & highs) that these offer....period.No other KZ has bass this clean and fast....period.The only criticism I can muster is to wish for slightly more warmth in male vocals, but KZ bracketed (partitioned) the bass with precision and bass bleed into the lower mids is nowhere to be found. If that nitpick is the only drawback, you'd be a silly individual to pass these up.*** IMPORTANT ***Remember that these are hybrids which contain balanced armatures. Balanced armatures are known for sounding absolutely pure to the point of piercing. You DO NOT crank the volume on your source the way you would crank it with a dynamic driver (DD) IEM. With a good pair of DD IEMs you can raise the volume levels to your satisfaction when you want to "party". It is not advisable to do this with BA driver IEMs and you shouldn't need to. Balanced armatures deliver crystal clear treble and are somewhat clinical. Yes, you can turn them up, but not the way you can with a DD. You will get ALL of the information at moderate volume levels. Some may consider turning the volume up to get more bass, but this will only increase the intensity of the BA. The ZST has been tuned with more than enough sub-bass so you shouldn't need to crank the volume to unhealthy levels for any reason. The uneducated or obtuse would whine about sibilance, when the real issue is that he hasn't followed protocol. Playing the ZST through a smartphone or power efficient DAP will likely result in the lack of the incredibly clean and FULL low end. This means he/she will mostly hear frequencies ranging from 100hz to 20,000hz (everything below 80hz will seem vaguely absent) and then he/she will complain that the ZST doesn't have enough bass. Don't be a softhead! Play the ZST through a sufficiently powered source. If you don't have a sufficiently powered source you should pick up the KZ ED9. The ED9 with the gold filters is the closest you'll come to the ZST's sound signature and you won't need more power to drive them. The ED9 gives about 80% of the ZST's sound. I may come across a bit rough on this matter, but I do it because I want you to remember this part of the review. A word to the wise is sufficient.The ZST has rocketed to the top amongst the competition. I have over 40 IEMs and the ZST ranks #1 in my sub-$20 list..Top 5 Sub-$20 IEMs (revised):KZ ZST ($18) - crystal clear highs and centered mids for a bass oriented IEMKZ ZS3 ($18) - organic lifelike presentationKZ ED9 ($14) tied with KZ HDS3 ($6) - open-backed & out-of-head presentationKZ ED10 ($10) tied with Winintone EB220 ($25) - Energetic and engaging presentationKZ ATR/KZ ED7 ($8+/- ) neutral..ish analog sound signatureThe final three are In no particular order because I usually pick one of them based on my mood. My ED3 'Perfection' didn't make the top five because I use them exclusively for the classical/baroque genre, but they are excellent. If you were to ask me which three KZ's I listen to most, my answer would be ZST, ZS3 & HDS3, in that order. Though the ED9 is technically better than the HDS3 it does display splashy treble on occasion. I modified my ED9 by removing the gold filter and placing a pinch of cotton (from a cotton ball) into the cylinder. Problem solved! My HDS3 is fun and doesn't sound like any of my other IEMs. That's the thing though, isn't it. It's not what is technically proficient but what you enjoy listening to the most. It's the whole point of this hobby. Your picks will vary based on your preferences.Also, I keep all of my IEMs that have detachable cables stored in a slightly larger storage case. See last photo below. I don't like constantly assembling and disassembling the cables with each use so I wind the cord and secure it with Velcro, then store the IEM fully assembled. Constantly connecting and disconnecting will eventually result in loose connections or failure, so storing them fully assembled ensures I'll get maximum life and minimum failures. The Velcro also grips the cases felt interior and prevents the IEMs from being tossed about inside the case with vigorous movements. Click on my name at the top of this review and scroll through my reviews until you come across the CoolSell or Folote storage cases. I always purchase the 2-pack and wouldn't treat my IEMs any other way.Rumor has it that Knowledge Zenith is now brewing a 10 driver IEM. My guess is that means 4 BA drivers + 1DD per side, but maybe it means 10 BA drivers per side. We'll have to see, but I can't wait to hear it because Knowledge Zenith rarely disappoints. If the ZSR is in fact a 10 driver per side IEM, then that means that Knowledge Zenith is sticking to their mission statement and reason for being, which is to ensure that you don't have to spend a mortgage payment for top quality audio. Rumor has it that KZ may have been licensed to mimic Campfire Audio housings (hopefully the "Lyra" but it looks like it might be the "Orion"). If this is true then I find it quite interesting that Ken Ball (owner/operator) at Campfire Audio gave license to Knowledge Zenith to produce a lesser version of his ground breaking IEM housings. Think about the implications! Campfire Audio for the top end of the market and Knowledge Zenith at the entry level. If KZ can deliver a well built highly resolute 4BA + 1DD hybrid or 10BA for $30+/-, then the established brands can no longer ignore the threat approaching quickly in their rear view mirror.What I'd love to see is KZ release:1) a simple multi BA+1DD in the ZS3 housing, but in a glossy black cherry offering a more refined ED10/ED11 sound signature.2) a simple multi BA+1DD in the ZS3 housing, but in a glossy midnight blue offering a more refined ED3 'Perfection' sound signature.3) a multi BA+1DD offering a more refined HDS3 sound signature, perhaps in TFZ's code 004 midnight blue/clear housing or even a piano black/clear housing.Knowledge Zenith has my full attention!"Baby steps to four o'cloooock......baby steps to four o'cloooooooock"(Bob Wiley from "What About Bob?")As a side note, I highly recommend purchasing your KZ's from Easy Earphones because, for me, he has always performed admirably in both sales and returns. My very first purchase from Easy (KZ ED10), back in June, arrived with an imbalance in sound. 'Easy' made the process of returning them.......well.......easy. Recently, when I received my order of two new 'Colorful ZST' earphones and one ZST upgrade cable, Easy included two KZ storage cases, of his own generosity. The nice carbon skinned leather cases were a nice touch. To top it all off, my order from China usually arrives here in California WITHIN 2 WEEKS of my order, whereas other shipments from China typically take four weeks. Again, thanks EASY! Always a pleasure doing business with you.The only other sellers I will vouch for are "KZ Headphones" who incidentally always shipped my KZ's with a zippered storage case.It looks like the Cosmos silicone ear hooks you see in the photos are available once again. To find them just click on my name to see my other reviews and scroll to the Cosmos ear hooks ($10 for 4 pairs).The ZSR is still in development and will likely be released in April 2017, but my "Add to Cart" finger is twitching.Come on KZ, "I NEED.... I NEED.... I NEED"(Bob Wiley from "What About Bob") :○Hope this was helpful.