CCA KZ AZ09 Bluetooth 5.2 Module IEM Adapter Wireless Waterproof Ear Hook Extra Long Battery Life Bluetooth Cable for ​KZ ZS10 PRO/ZSN Pro X/ZSN PRO/ZSX/AS12/AS16/ZAX CRA/C12(C pin)

These work perfect with the KZ ZST iems. They are light and comfortable and stay even with head shaking. Sounds just as great as plugging in with an audio jack. The case is on the large size, definitely have to throw the case in a bag unless you don’t mind bulging pockets. The case also fits with the iems attached. Very happy with this purchase.

I bought these as a test to see if I would like the style and fit before dropping $80 or more on a good pair. Connection is awesome, regular earbuds don't connect for me from the interference in my environment, these are a solid connection that hasn't failed or dropped out once. They are more comfortable that I would have thought. The battery life is great, like in excess of 8 hours for me. The volume could be a little more as they seem underpowered sometimes. There have been a couple of times that I wished I could turn them up a little more but they were already all the way up. With BASN iem's the sound is fine with no buzzing or hissing in the background. For my purposes I can't justify buying a more expensive pair just for the louder volume. It wasn't like it wasn't loud enough to hear, just wanted a bit more. After more than a dozen pairs of wireless earbuds($30~$120) that wouldn't keep a connection more than 5 seconds without dropping signal these are the best listening experience I've had. Way better than expected.

These bluetooth adaptors work very well to turn in-ear monitors into amazing wireless earbuds. I had no issues pairing them to my MacBook. The battery life is really good, and the case only needs recharging every 10 days or so.Two small caveats that cost them a star for me: 1) one of the pair is a bit loose in the connection. Not super loose, but the monitor will unplug if you put too much pressure on the connection and 2) that same hook can be a little finicky seating down in the case to charge. That really only happened once, but partly because ever since it did I'm very careful to make sure it is well seated in the case.But combining these with a decent set of monitors will give you sound quality you'll never match with any regular earbud. Definitely worth the price.

UPDATE: I finally got in touch with the company, you just have to push your way through Amazon customer service first. I dont remember it being so complicated in the past? They said immediately they'd send a replacement and I just got it in the mail! quick and easy :)Original Review:I bought these with the wired KZ EDX Pro in-Ear Monitor Headphones so I could swap them out between bluetooth and wired. Sound quality is great for the price, I find them comfortable and they dont slip out of my ears when I work out (!!!) I was so happy with these. but after 4 months the right earhook started generating this static scratching sound and now is unusable... I'm not sure what the lifespan on this stuff should be but 4 months seems pretty bad...I feel like they would probably send me a new one if I could figure out how to contact the company? it doesnt seem possible to contact them through Amazon...

Although this is a 78mm 2-pin Bluetooth adapter, it does not fit HEXA!It is very loose when connected to HEXA.However, it does connect to EA500. So, be aware if you want to purchase for your IEM.Secondly, when it connects to the PC, it automatically recognizes it is a hang-free device and a hang-free device has a horrible sound. You have to do a little disable/enable in the Bluetooth setting. And that is a little trouble to do so. But you can definitely find instructions on YT.Finally, it is kind of annoying whenever you need to connect to a phone or PC, you will need to put the IEM back in the box. Otherwise, it won't recognize.Besides all these little things, this Bluetooth adapter is very good. The sound is a little lower than connecting with cable, but if you connect to a large volume IEM such as EA500, that problem is solved perfectly. The sound quality is good.Overall, I am very happy with this purchase.Updated: It is dead in 2 two days with the right ear module not charging. And I already threw the box away, so I cannot return it.Do not buy it, I repeat, Do Not Buy It!!