First of all, please don't consider me as an audiophile, rather a Pro-Listener with critical listening ability. I am inclined with neither low nor mid nor higher frequency ranges. Rather I prefer a capable audio gear that can produce any sound signature with EQ in line with the source audio, whether flat or balanced or bright or v-shaped or warm and can even please a basshead or audiophiles in fear of bass. And I want my audio gear to produce sound the way I want it to produce sound as per my different preferences depending on my mood at any point of time. So my review will be based on KZ ZAS's capability of producing different kind of audio signatures. Also note, I said "in line with the source audio". That means, the source audio signature depends a lot on how that song/music has been recorded and how the mixing is done.
Now lets get into the detailed review.

In the box:
Same black KZ box with beautiful IEMs, new upgraded cable and worst quality audio tips. Though the new upgraded cable is still not producing sound as revealing as my silver plated cable which I bought separately for my previous KZ ZSX.

Build:
Very light weight in comparison to previous KZ IEMS even with smaller size. And the Silver-White model really looks gorgeous. This time KZ chose a little narrower nozzles. However, I am doubtful on the durability of the plastic shell used here. But, majority are not rough users like me. I broke my previous KZ ZSX as accidentally I sat on them. Still, this IEM needs to be handled with a tiny more care than previous models.

Fit:
The stock ear tips are useless. At least for me. I am using the large size silicon ear tips provided with JBL in-ear headphones which I took from mother's and sister's headphones as they use the medium size. The ZAS shell fits well in my ear and I am sure will fit well with anybody with normal ear size and the light weight really helps to keep it plugged in for longer duration. My rating is 4.5 upon 5 for fit.

Audio gears, apps and source audio I have used:
Device: Mi 10i both with and without Shanling UP4 Bluetooth DAC with LHDC. I prefer LHDC(900 kbps max) over LDAC(990 kbps max) as LHDC supports EQ in Shanling UP4.
Source Audio: Apple Music 24-bit/192 khz Hi-Res Lossless and my collection of Lossless FLACs including many 24-bit as well.
EQ app: Poweramp Equalizer. I have Wavelet as well. But Poweramp sounds like as if I have removed a curtain over Wavelet. Also Poweramp has more granular level audio tweaking capabilities.(Email me at [****] if you want to best EQ with Poweramp)

Audio Quality:
As I prefer, this is a very very capable IEM. In a word, just awesome. And this time KZ clearly moved from amateur to premium.

Soundstage - Soundstage is wide but slightly less wider than ZAX. However, I am yet to find out the best fit ear tips for this IEM. JBL ear tips working well. But ear tips with stronger grip to ZAS's nozzle may change this experience.

Lows/Bass - Very very deep and with so much detailed. Lower, mid and upper bass are very prominently present with ZAS. I will rate it 4.9 upon 5.

Mids - Not recessed at all as we experienced with previous KZ models. Mids are also prominently present and detailed. However, lower mids need a bit more improvement. Female voices sounds really fantastic. Male voices are good but not as good as female voices. So, KZ has to work little more with male voices. For mids, I will rate it 4.6 upon 5.

Highs - You are not going to miss any element in the music you are playing. ZAS highs are very much detailed and accurate. But not fatiguing at all even when I EQ it for bright sound signature. For highs, my rating is 4.8.

Now lets look at how well it responds to the EQ that we can change its sound signature based on our preference. You can easily EQ it to any sound signature as per your preference. But you can't make it very bright or as harsh as ZAX is capable of. And Audiophiles, don't worry at all for ZAS's bass capabilities. With EQ, you can reduce it to as recessed as possible and it will never overshadow mids and highs. And overall my rating for audio quality is 4.7 upon 5.

Conclusion:
KZ ZAS is a very very capable IEM. If you are a pro-listener, this a very good IEM with Rs. 7999 price bracket for you. Not sure, if any other model or brand compete with it within this price bracket. So far, satisfied with its performance.

I'm very thankful to headphonezone Gurus to provide me right guidance as I'm not audiophile yet, but music crazy person for last 47 years. Their excellent services and lightening fast delivery system fulfilled my questfor music gadgets. Kz - zas is a excellent piece of IEM. It's very light weighted, you can wear it whole day comfortably, and it fits perfectly in my ears and the silicon tips of big size gives me tight fit from stopping outside noise. So I feel it's made for my ear only. Esthetically Black colour is good with golden monogram and lining is enough to turn heads; and with smoky transparent otherside reveals inner parts. Non tangle wire is of bit avarage type, but doesn't look cheap, 3:5 mm jack feels quite sturdy. Mine one is with Mike which helped me to handle calls easily, it works perfectly.
Main thing is it's sound performance:-
If you are using CD quality source of music, you won't need any DAC/ AMP to enhance the sound quality. Some may feel it little brighter or some may think it's little loud. But Just keep the equalizer Flat/ Normal of your digital music player ( good music player, like Nuetron, Onkyo, power amp, hibi, or Samsung music) and you will get fabulous sound. The puchy bass, well maintained mids , clear vocals and perfact treble, is very clear, detailed and pleasant. I am able to identify most instruments and it's locations while hearing Music.The Bass lover will love it, but it's not overpowering of hampering other frequencies. I also love to hear my bolliwood files in Mp3 (128kbps) as it sounded with good clarity and detailed with good bass.
The exceptional performance I get with my Tidal app music and flack files , using the USB player pro application (android)using USB to 3:5 headphone jack converter on My galaxy S10+. And when I use my Shanling U 4 DAC/ AMP , KZ-zas sounds brilliant.
Thus my combination of Galaxy S10+, with USB Player Pro, app along with Shanling U4 DAC/ AMP, with Tidal or Spotify and Falck files are giving me heavenly pleasure of Music;
still I am not audiophile but Crazy for Music.
A lots of thanks to headphonezone Gurus for providing me right kind of help and guiding me to create my possessions of right and proper music gadgets for my kind of Music. . So let the Music play on....!

These are simply awesome. For its price, these really punch above their weight.

They are an upgrade over Z10pro. Treble is not fatiguing yet detailed. The bass is really impactful. Mids are not recessed. One thing I would change is the tips. The stock tips are extremely flimsy. The cable on the other hand is so much better than what was supplied with the z10pro.

Anyone starting their audiophile journey, these are a perfect entry point. you won't be disappointed.

I loved listening to music on my hifi system set up and was looking to listen to high quality music while travelling or when I can’t make it loud on my home system.

As it was my first time listening to music on In Ear Monitors besides, apple and other phones packaged bundles. KZ ZSN Pro X is a much better experience than those. But if someone is looking for good quality high definition music listening than I recommend ZAS any day and is worth the extra investment. I have upgraded my wire to blon balanced and use Fiio BTR5 for music listening now.

First time in my life I bought IEM and also First time I bought headphones this expensive .
Last expensive headphone I bought was 3.5K one.
First I worried about sound quality before purchasing this IEMs because I never Paid 8k for headphones.
But now I feel . I made a right decision buying KZ ZAS,
These are Great headphones also louder than regular in ear Earphones .
Better lows , mids & highs .
This IEMs Never overpowers anything , perfect for those who love balanced sound signature.
If your are buying this headphones then make sure you buy high quality Eartips with it .
If you already own a good eartip set then no problem .
If your Basshead and confused before buying them then don't think and buy them , you will love it .
Good , nice and comfortable IEMs .