KZ AZ09 Bluetooth 5.2 IPV5 Waterproof Noise Reduction Bluetooth Module Upgrade Cable Ear Hook for ZST/ZSTX/ZS10/AS06/AS10/BA10/ZSR/ES4(B pin)

After ordering 2 different sets of IEMBT cable adapters from KZ (TRN BT3S and KZ HD gray cable) and I picked up the AZ09 against some of the reviews and was pleasantly surprised that 1) finally my callers could hear me properly. 2) it connected very fast like the KZ HD but I could use just one ear if I wanted and 3) the case is slick, magnetically grabbing them into position and charging them on the go.The led indicator is helpful and these finally let me wear my glasses much easier than the other two which I had to constantly trap the wire underneath the legs so they wouldn’t fall off.The BT3S were not bad mic wise but its not BT5.2 and connection was so so. Cutting in and out with a snapping audio cut everytime was irritating and replacing iphone clicking sounds with these annoying loud beeps sucked. Latency was terrible as well, had to re-pair them quite a few times to get them to sync up again.The KZ HD set was a good one and I hesitated returning them but the one main flaw was the length and arrangement of the wire. If they update the BT3S with the guts of the KZHD and shorten the cables a bit they would have a winner. Alas whenever I would take off the left one it would drag the mic and buttons to the back of my neck and that SUCKED. As a listening set it sounded great. I might say maybe better than the AZ09 by a bit. Louder and cleaner. By 5-10%Overall I am very satisfied with these AZ09. Sounds close to wired sound and I have them paired with KZ ZAX Metals in black which sound fantastic on them. Little bit of noise floor but tolerable for a day to day device. But they win all around.Definitely recommend them.

I bought the AZ09 to pair up with my KZ ZAX and iPad Pro 11 (2nd Gen). The sounds was great, pairing was easy. After about 10 minutes the audio skipping started. Followed the standard instructions and removed the device, rebooted my iPad, re-paired and same thing happened. I than paired to my iPhone 11 and no audio skipping with a super stable connection. I than paired them to my iPad Pro 10.5 (1st Gen) and again no audio skipping, so I relegated the AZ09s to the closet never to be heard of again. However, I went on the internet to search out this issue on the iPad Pro 11 and it turns out that there is a bug with “hey Siri” enabled and audio skipping. Turned off “hey Siri” and problem solved. I am now finally enjoying the AZ09s full potential. They do produce a slightly warmer sound signature. Bass and mid-bass ranges will be slightly more pronounced, mids and highs still sound great paired with the KZ ZAX. You will also get a little bit of audio compression but the is the price of Bluetooth. There is a high performance mode that cuts the audio lag in half meant for gaming and works as advertised. Battery life is excellent with fast re-charge rate. If you are getting audio skip on you iOS device, disable “hey Siri” and try again!

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 priceCons- 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

I'm just trying this out now, straight from the packaging. It comes fully charged. I used a pair of cheap ZST in ears I got also off Amazon a few years ago to test them.Pairing and setup was as easy as it could possibly be! So the Bluetooth tech is good tech inside!The voice samples that tell you the device is on/paired/etc are REALLY poorly recorded, which gives you the impression that the audio quality won't be good. But that is not the case.But the actual audio quality is quite close to a cabled connection, the signal has enough drive to push out bass frequencies on the ZSTs I used. Frequency response seems to be pretty flat and true, with maybe a hump around the 1-1.5khz range but that might be the ZSTs. Triple tapping the earpiece will put the drivers into high performance mode which gives a small boost in volume.I'm going to use these in the gym today and I'll edit this review to provide the battery percentage. But so far, this is an incredible buy!!!