I bought KZ ZS10 Pro’s a while back, and have been loving them since, and decided to go ahead and try this bluetooth set for them. I figured at the price point, even if it didn’t work right or was just unpleasant to use, I wouldn’t even be that upset. That said, I absolutely love them, instead of meeting expectations, they blew them away, and I’ve been super happy with them in almost every way. Also sorry this is so long….

Small side note, the cons list is *not* longer, it’s just more specific because I kind of had to nitpick a little bit, I genuinely don’t have much bad to say about these personally, the star rating should speak for itself.

TL;DR – If you want these for your pair of KZ IEMs, just get them. Do it.

Pros
– Sound quality – Obviously when paired with a set of IEMs that sounds good, I didn’t notice any real quality degradation. My ZS10’s sound just like I expect, and that’s exactly what I wanted
– Comfort – I wear these for 10 hour shifts at work, one ear at a time, swapping at lunch, and they haven’t been uncomfortable yet
– Battery Life – They will last well past 6 hours of continuous use, when I make my swap at lunch, I’ve been at around 40% life, and that’s 5.75 hours into my shift
– Connectivity – As of yet, I’ve not seen them even hesitate to connect to my phone, I open the case and I hear the little voice say “Connected”, seamless and super fast
– Build quality – While the case will be mentioned later, the bluetooth bits themselves are awesome, they’re solid, the buttons are well placed, and I’m not nervous at all that they’re going to fall apart or break on me
– The Case’s Function – The case genuinely belongs in both the pros and cons, it’s here in the pros because it does have a USB C charger (that it comes with, a cable at least), it has never had an issue with actually holding the modules to charge, and it has a foam bit in it to hold the IEMs in their well safely. It’s well thought out, and I think it does its job great
– Buttons – There’s physical buttons. You can’t press them accidentally, you won’t double tap if you didn’t mean to, they *can* be pressed with just one finger, they’re leaps and bounds above dealing with touch sensors. Yes it’s technically a “moving part to break” but they seem robust and they’re pleasantly tactile
– Value – While these obviously aren’t capable of producing sound by themselves, even including the price of these in conjunction with the ZS10 Pro’s, I spent around $75, which puts them at about half the price of the (original) Galaxy Buds I’d been using, and I like them so much more in terms of comfort, sound quality, and the fact that there’s no touch sensors
– Call Quality – They are described to me as “7/10” and “about what should be expected from a good quality pair of true wireless earbuds”, and I consider that beyond good enough for the price

Cons
– The Case’s Build Quality – To be fair, I don’t think it’s *that* bad, and it seems sturdy enough, but the hinge is a little flimsy when open. It also is a little chunky, but considering the size of the modules+IEMs, that’s not surprising(and not that bad)
– Button function – While I like that there’s no companion app, it’s a little unfortunate that you can’t change what the buttons do – For example, I’d like a double click on *either* side to do “Next Song”, but double clicking the left side’s button does “Previous” instead, which I almost never want. (This is a minor complaint for me though, I do have a smartwatch that I can use to control media anyway)
– Where the IEMs connect – Again, this isn’t a huge issue, but I did cut away a tiiiiny bit of the plastic around the connector that connects to the IEM, it doesn’t quite fit around the IEM’s connector, and feels like it should push all the way in, but there’s like another 0.5-1mm of length on the contacts. It felt fine how it was, and I’m sure it would have been, it was holding just fine before I modified them, but I feel cutting away a tiny bit of that plastic surround made a bit of a better connection
– If you have a smaller ear, or the original cable that comes with specifically the ZS10 Pro’s(potentially others, I’ve only ever had these ZS10’s ) doesn’t fit you well, these bluetooth bits may not be the best fit. They fit me *perfectly*, but the original ZS10 cable does as well, so that may be something to consider if you know your ears are smaller than average
– ANC/Ambient Modes – I don’t think there’s any ANC or Ambient modes, or if there are I haven’t figured out how to get them active. This is *not* a con to me, those aren’t features I want, but I figured it’s worth a mention

Have been using them a few days now and this what I think so far:
Sound Quality: The sound quality with these on my KZ ZS10Pros is on par with what I’d expect from a decent sub-$100 set of True-Wireless headphones–which is to say, perfectly acceptable. Bass is a bit over-emphasized to my ear and the highs are almost too-crisp, like a sharpening filter or eq preset is being applied. To me it’s perfectly usable for casual use, but if you listen critically you may well notice the compression artifacts, particularly in songs with wider dynamic range and in older remastered recordings where there is tape hiss. Honestly, if the ZS10Pros were not so dang accurate, I probably wouldn’t have enough resolution to notice.

Interface: If you come in knowing what to expect from cheap true-wireless setups, there are no surprises here. The buttons are clicky microswitches, one on each earpiece, with different commands delivered different numbers of clicks or holds. The “power on”, “power off”, etc. voice prompts are delivered in a comprehensible but almost cartoonishly heavy accent. No volume control, so you’ll be relying on the device you pair to for that. No app support, no EQ. There is a “high performance” / low latency mode…I haven’t had time to mess with that much.

Battery life: Used for 2-3 hours a day at my desk at work for the last couple of days without charging the case and no problems so far.

Range: At least as good, if not better, than other bluetooth headphones I’ve used. They make it to the coffee pot and back.

Overall: I wouldn’t buy these (plus a set of IEMs) as a standalone product, but if you already have KZ IEMs and want to get more use out of them in casual listening situations, the value proposition at this price is more than fair. I’m happy with them. I might have been happier had I waited for the AZ09 Pros (those apparently have a Qualcomm chip and AptX support) but anyway, there it is.

These are amazing for the price. If you get a pair of KZ IEM’s and combine it with these you’ve got a better sounding IEM than most if not all true wireless earbuds out there for a fraction of the price! If you want more and your purchase more expensive IEM’s than these don’t do it justice, for example, I bought the 7hz dioko and timeless, one being 100 and the other being 220. Paired with these it doesn’t sound nearly as good if used by the fiio utws3 or 5. The utws5 sound MUCH better with better and more expensive IEM’s and if you’re wanting an upgrade I’d recommend these, the utws5 + 7hz timeless/dioko sound better than ANY wireless option including headphones. Wired is a different story

Just received them today and sounds really good for the price! Doesn’t get LOUD but more than adequate for my needs. If I want to get more serious with my music I’ll just go for hard wire. Didn’t bought these to replace hard wire. Just to use them at work. The reason for 4 stars is that It didn’t fit the KZ ZSN Pro very good. It was too tight and didn’t cover the entire base of the pin connector. I also own the KZ DQ6 and had better results. So to get around that issue with the ZSN Pro, I did a self mod. I cut the plastic ring around the pins with cutting pliers or a nail nipper. I slowly cut it until I hit the base where the pins end and then I just clean it up a bit. Get rid of the plastic shaving. Now with the mod, I can use my other 2 pin IEMS! In the picture above I have the FIIO FD1 connected with the KZAZ09.