The Vsonic GR07X retains the form factor and design of the GR07 versions before it. It features a new driver (still biocellulose-based it seems) and allows for swapping the cable below the Y-split with a 2.5mm connector (snaps firmly into place, seems quite sturdy). Thus if the cable were to fail at the jack end, it should be possible to easily remedy that with any replacement.
 
Currently it ships with 2 included cables, 1 standard 3.5mm plug cable, and one balanced cable  with a 2.5mm plug end. I also got a pack of spinfit tips included with them (small, medium, large sizes). Check with your dealer as I'm not sure if that will always be the case.
 
 
The GR07X sounds better to my ears than anything I've heard so far, including armature IEMs like the single BA Etymotic ER4S and the quad-BA Noble 4 Universal, single dynamics like the Dunu Titan 1, and full-size headphones like the biocellulose-based Audioquest Nighthawk or the planar Hifiman HE400i.
 
 
- Tip rolling is recommended to find the best presentation of the sound for you and your ear anatomy.
 
 
Compared to the GR07 Classic (I've heard 4 pairs of those) the GR07X features:
 
- More linear and neutral frequency response (less bloomy lower mids, tighter bass, treble peaks well-neutralized, very well-extended).
- Retains the crisp articulation of the GR07 Classics, and with improved micro-resolution.
- Also greatly improves imaging, soundstage/ambience/low level clarity and overall clarity across the spectral range.
- No vacuum seal or deep insertion required, which further helps wearing comfort.
- Materials seem refined slightly, the cable exit piece from the IEM has a tighter fit and no subtle glue residue between it and the IEM body. Cable is slightly more rigid than before.
- Improves on all aspects of the GR07 Classic, with no induced negatives whatsoever that I can perceive.
 
 
Listening to the GR07X, more than ever before for me, feels almost like a privilege. The articulation and clarity it provides is spectacular, even more so considering a single dynamic driver is providing it. It crackles and textures like a warm campfire.
 
Removable cables at the earpiece side might be a future feature to include, however I use the included earguides and never noticed that side incurring any stress. And removable connectors, unless designed to screw firmly into place to avoid wiggling and degradation of the connection, would be another failure point to worry about.
 
 
Very highly recommended if you have the money and are looking for very a well-balanced IEM, and sometimes breathtaking levels of articulation and clarity. I can only give these the highest rating, considering I find them (at double the price) to be as good of a deal as the GR07 Classic is.

 
 
I was contacted by a Shozy representative and offered to evaluate and honestly review the Zero IEM, after letting it play around 200 hours of music. They were delivered to me free of charge, so keep in mind this potential bias. I will try to be as honest and objective as possible. I own several single dynamic driver IEMs, aswell as a few balanced armature designs.
 
I tend to prefer metal and rock music, aswell as soundtracks, and 80s music.
 

Design:
 
The Shozy Zero is a very small, very light-weight IEM. The prominent feature is the Rosewood housing, with what feels like metal nozzles (or maybe plastic, not entirely sure), and with cable strain relief by the housing. Cable has a slightly rubbery feel, with some memory effect. Overall the cable is quite nice, reminds me slightly of a slightly thinner Vsonic GR07 cable, and a transparent cover on it reveals some textures and colors of the internal wires. Straight 3.5 jack also from rosewood, with a slight rubber strain relief. Y-split is also Rosewood, and there is no cable cinch.
 
When inserted, the Zero creates a seal with your ear canal, meaning its Dynamic driver unit seems to not use/require ventilation. If you move the ear canal through big facial movements, the frequency response changes as the pressure in the ear canal changes. Typically not something you notice in most use cases, and I would imagine that foam tips would avoid this (though I haven't had the chance to try the Zero with foam tips).

 
Sound:
 
My Shozy Zero is a generally bass-leaning, smooth sounding IEM. Depending on tip choice, the sound can be quite sub/bass-heavy, or with some tips a slightly more balanced presentation is possible.
 
Micro-detailing is perceptually good, thanks to the even frequency response and non-peaky treble. Macrodetail/speed is probably where the biggest giveaway to the low price lies. The bass is quite big and deep, and fairly slow and loose, and slightly boomy-sounding, though that is probably more from the sub-bass emphasis, and the bass generally doesn't really bleed into the mids.
 
The mids are smooth and even, sitting a few steps behind the sub-bass and bass. The mids are slightly thicker, as opposed to projecting transients forward. This results in a dynamically veiled, slightly warm, inoffensive midrange. Instrument separation and layering is quite good despite this, and something like atmospheric synths can quite clearly be heard even while distorted guitars are taking up room in most of the midrange.
 
The treble has a certain level of micro-snap, but isn't nearly as dissecting as a balanced armature driver or some dynamic drivers. It seems to saturate fairly quickly in terms of how well it separates dynamically, and using EQ to create a peak around 6-7 KHz where drum transients tend to dominate doesn't really increase the dynamic level as expected, but rather boosts the volume without increasing the aggression of the sound. This again leads to a smooth sound which doesn't really immediately impress with its decay or technical prowess, but also allows you to avoid sudden aggression from music.
 
The general sound seems to be steadily held at a comfortable level thanks to the, dynamics-wise, smooth presentation, with smooth midrange and treble, and the bass having some depth and heaviness to give a bit of movement to the sound. Layering is quite good considering the smooth dynamics, and the soundstage, while not holographic or 3d for me, has good depth, I suspect the bloomy bass gives the sound in general a slightly longer "release" and fundamental vibration which makes them sound naturally slightly reverberant and roomy, rather than being completely dry like speedier IEMs.
 
Considering the fairly variable sound of the Zero depending on fit and tips, the above might differ more or less.
 

Comparisons: 
 
Zero Audio Tenore ($40-ish):
Probably the most fitting comparison I can make, since they are both small (possibly both using non-ventilated microdrivers), and both command a fairly similar price point. They both have a fairly similar presentation with withheld dynamics and slightly more distant sounding drums as a result. The Shozy has a much more moving bass however, the Tenore is quite dry and light in comparison. The treble of the Tenore I perceive as slightly more accurate, but the Shozy has slightly better transients there. Ultimately the Tenore also feels more compressed sonically, not quite getting the layering of the Shozy, possibly due to the bass movement and depth of the Shozy.
 
Vsonic GR07 Classic ($99):
Twice as expensive, the GR07, on a technical level, is entirely in a different league. Drums are not held back or restrained or evened out, they can pierce through anything. The difference in design goals between the Shozy and the GR07 is interesting to hear. Even when using EQ to make the GR07 treble significantly more dark than the Shozy treble, the GR07 still snaps as quick as Bruce Lee in his prime. Also apparent though, is that the bass (along with the general sound) of the GR07 is more armature-like, and just won't bloom with the same gravitas that the Shozy Zero bass does. The Zero, when going back and forth between the two IEMs, definitely is more gentle, more about bringing the tones closer to you, and not nearly so concerned with slapping you in the face with transients as the GR07.
 
 
Overall:
 
Despite the Shozy Zero being neither my favored sound signature nor presentation (I prefer a bass-lighter sound with strong dynamic separation), I can't really fault it in any area. The design inherently needs a vacuum seal (which I'm not a fan of but foam tips might help with that), and driver flex (a crinkling sound when pressurizing the ear canal while inserting using some tips) has been observed by me aswell. The driver seems to be affected by low or high pressure in the ear canal, which a ventilated design generally won't encounter. The Zero should suit someone who enjoys a non-offensive sound, who doesn't want aggression in the presentation, and who favors a sound that leads quite vibrantly with the fundamental notes of the music.

IEMs I own and have used extensively before: Vsonic GR07 (single dynamic), Vsonic VC1000 (dual BA), Etymotic HF5 (single BA) (all around or slightly above $100).
 
 
Fit and Comfort
The housings were smaller than I was expecting, very light-weight. The cable closest to the housing has a metal wire that you can bend to your desired shape around your ear. The IEMs are not ventilated, so can create a vaccuum feel in your ears with some tips. I am sensitive to this though and it did not bother me with these IEMs. Depth of insertion can be quite shallow if desired, no need to shove them in deep to get a good sound.
Wearing a hat over them might put uncomfortable pressure on the housing into your ear. I tend to use mine only at home, and my GR07 are my on-the-move IEM, with smaller housing, and an angled plug for mobile use.
 
Included Cable
Very good feeling cable. Feels very strong (supposedly is very strong), virtually no memory at all, won't tangle easily, terminates in straight metal-covered 3.5mm jack. No shirt clip included, I was able to get the wire over an old Soundmagic shirt clip (wire is 4 smaller wires braided, with some careful manouvering you can get 2 or more wires over even smaller shirt clips). Shirt cinch exists, a transparent plastic tube that can be slid up and down.
 
 
Overall Frequency Response
Very very neutral. You can make some slightly adjustments depending on tip choice. Lowest bass is represented, but slightly rolled off in terms of volume. From mid-bass up they are very neutral sounding across the range. Nothing pokes out, nothing dips down. Very well balanced, I would not hesitate to do critical listening with these.
 
Bass
Quality is great, very textured and fast decay as per usual with BA drivers. Midbass is capable of rough "hard" texture and rumble with good attack when called for. Bass rarely takes centre stage in terms of volume, is mostly fills in underneath the mids and treble in a quite airy, layered way, surprisingly spacious and "stereo" at times. For most acoustic and orchestral stuff I feel the bass amount of pretty much spot on for creating a realistic presentation without overly emphasising the bass. For most orchestral stuff again, bass perfectly fills out the lower midrange and can provide a great sense of body and depth to sounds, but it's always in moderation and with a sense of slight shyness.
 
Mids
Very very good. The decay and clarity in the midrange is one of the highlights of the Noble 4 Universal. Quite present midrange, with superb dynamic integrity and transparency. Moments in soundtracks in films where the orchestra calls for sudden stabs of brass or strings really do jump out with body and weight.
 
Treble
Very detailed and transparent aswell, very natural extension from the mids. They can provide a slight textured bite in lower and high treble when called for, however are also capable of very realistic, natural, presentation. Despite the neutral frequency response, they render distorted guitars with very good crisp texture when called for. Can be aggressive or smooth on the surface depending on material. Very versatile.
 
Dynamics
Excellent dynamics with a very clear, fast feel across the range. Compared to the Vsonic GR07 the Noble 4U has much superior texturing, speed and layering in the mids and lower mids and bass, and the precision and capability both in soft, distant sounds and snappy, loud close-proximity sounds is very lifelike and impressive and adds to the effortless depth. I did notice when first using the Noble 4U that the treble texture and overall slightly dry and scratchy "feel" on metal music really reminded me of the GR07, but without the uneven frequency emphasis of the GR07.
 
Soundstage/Presentation
The soundstage (or the integrity of low-level details that help create a sense of room, size and space) of the Noble 4U are capable of is impressively natural, layered and very, very convincing. It has none of the slightly cramped or diffuse depth of the GR07, VC1000 or the Etymotic HF5. It can sound very wide, very deep and very convincing if the material calls for it. Compared to the 3 IEMs I just listed, the Noble 4U is the only one where it will genuinely sound like you are in the space the music presents. The cohesion of the stereo field from left to right is superb, and the excellent clarity and speed makes it very, very transparent. By that I mean, when listening to the Noble 4U, if a song is presenting you a big orchestral room, you can clearly "see" all the way to the back of the room, nothing obscuring subtle reflections or nuances in sounds. The GR07, VC1000 or Etymotic HF5 all feel like there's a slightly layer of smoke in the room, and while you can make out what the room looks like when you listen to them, you generally only see clearly the sound that is closer to you.
 
In short, the presentation of the smallest of nuances in ambience, even when the musical passage is blasting brass or other richly textured sound, is very clear, and you feel and hear so many layers into the distance.
Couple this with the dynamics across their range, and they really are great at presenting at immersing you in orchestral and acoustic recordings where the room sounds are featured more prominently. You can close your eyes and just completely be in that space, the neutral FR further helping a very convincing presentation with no unnatural frequency spikes or dips or an overly prominent bass or treble.
There seems to be no  noticable phase issues creating an articial sense of space either. For metal material the sense of cohesion in attack and centre stage is superb, no diffusion really noticeable.
 
 
Summary
 
The Noble 4U is a very neutral IEM, impressively so, no area feels emphasised, they don't sound bassy, bright, or overly midrange-focused.
The entire frequency range has immense clarity and ability to create an open, spacious feeling to the sides, in front and even above you. Dynamics are very natural and orchestral material can sound very lifelike and 3-dimensional, both in how the room extends out, and how the instruments will jump out at you when called for. Surface texture can be aggressive when called for thanks to good attack and decay, making metal and other music satisfyingly aggressive sounding.
Perceived cohesion in sound from bass through treble is very good.
The way they very faithfully reproduce the material played without any real coloring is their absolutely strongest attribute. you can be playing songs where you are enjoying the sound, but you might not be impressed. Then you switch to a song where the recording is focused on reproducing the room it was recorded in, and suddenly you realize/remember the capability of the Noble 4U. This is one IEM where once you play something that shows what they can do, you will start aiming to find material and music that has those aspects for the Noble 4U to reproduce. I find myself playing specific songs over and over just because of how well they are recorded and how utterly convincingly it feels like I have a guy 3 feet to my right playing a steel-stringed guitar in a small-ish room.
 
Overall, I personally consider the Noble 4U to be an extremely satisfying, refined, mature upgrade from the Vsonic GR07, Vsonic VC1000 or the Etymotic HF5. Compared to all these, the Noble 4U is impressively more capable in all areas of their sound, where the others in comparison have very noticeable "deficiencies" in either perceived soundstage, frequency response linearity, or areas of their FR where their drivers are not able to reach nearly the level of clarity or dynamic integrity of the Noble 4U.
 
I fail to find any weaknesses in their sound whatsoever, subjective or objective. These are spectacularly transparent, neutral, natural, impressive-sounding IEMs.

After owning the Vsonic GR07 Classic Edition for about 2 months or so, all I can say is these are absolutely brilliant.
 
Very articulate, fast/dry sound. These will extract details almost to a fault, to the point where classical music isn't realistically presented for the most part, due to overly in-your-face presentation.
They are quite neutral, however have a full low-mid area and a 6.5kHz peak, a build to a 10K peak, then a dip around 12kHz and then another peak above that (se for example  innerfidelity for a detailed FR graph).
 
For critical listening, they are probably not as spectrally linear as you'd need.
 
However, they have a mildly scratchy/papery quality to them that is irresistible to me, thanks to the 6.5KHz peak and the overall extremely vibrant, articulate response across the spectrum (they never feel like you have a smooth, solid wall of sound against your ears, but always manage a detailed, vibrant, rippling surface that effectively prevents listening fatigue).
Drums and guitars, and other sounds with snap and texture, are absoluely superbly presented. Thanks to the great fast response, 6.5KHz focus point and fast decay, movies with gunshots and other action-related sounds with fast transients are also rendered incredibly snappily and crisply.
 
Sibilance can be a problem in the 6.5KHz area, however after adjusting to it most other headphones sound overly polite in comparison.
 
Overall a light, airy sound with great articulation and dynamics across treble, mids and bass. The papery aspect is particularly descriptive of them, take a paper and rip it slowly, that type of dry, quick, scratchy, crackly sound is the trademark of these things and adds the richness they possess, yet they are extremely clean and free from distortion.
 
For the current price of 100$ I really cannot recommend these enough, they have a unique signature and presentation that is incredible for metal/rock and action films, and will deliver a very detailed sound in all cases, as long as absolute linearity in frequency response isn't critical. I have a pair of Beyerdynamic DT880 which have a similar balance, and those feel like a very good linear companion to these, lacking the pronunced 6.5KHz area and the dip above it. Even with the Beyers and their more natural, airy, slightly more spacious sound I still reach for the GR07 alot, particularly for action films.