YINYOOKBEAR BT5 Bluetooth 5.1 Upgraded Cable Wireless Adapter Cable with 6 Hours Playing Time Bluetooth Cable for KBEAR KS1/KS2/Lark/Robin/Rosefinch/CCZ Melody/Coffee Bean/Warrior (tfz, Black)

I would not recommend this adapter for exercise/movement; the portion that rests behind your ears would not even stay put for weightlifting. Also, the wire is too long and the bulky control pieces get in your way. Lastly, the adapter significantly raised the minimum sound level on my earbuds, to the point where it was way too loud for my ears even at the lowest volume (not sure if it makes a difference, but for reference this is what I used: Apple Music via iPhone 12 with Rosefinch earbuds and the TFZ adapter model).

As others have mentioned, the connection between the earbuds and the Bluetooth cable isn't very secure and tends to come loose if you move around too much they'll come loose.But if you're just walking around the house cleaning this is a perfect solution!

At first blush, this looks awesome, but the first giveaway is the charging port cover. There is no lip, no subtle depression that allows you to lift the cover in order to charge this. Each time, I have to look for something sharp to pry the thing open. Moreover, this thing lasts about four, maybe five hours (on a single charge) if you're lucky, and so if you listen to a lot of music then this charging port debacle gets old quickly. This st also does not come with any of those HiRes (APTX, LDAC) low latency audio formats, so scratch that off the list. This might seem like nitpicking, but these guys make IEMs, many of their earbuds aspire to the top of the line or at least reference grade audio. There's little point connecting decent IEMs to a bluetooth device that can't take advantage of the capabilities. Also, the connecting pins don't fit as well on many models listed on their product page. I tested this with KZ Krila, KZ Castor, KBear Storm and some others. I won't advise venturing into physical activity with these on for fear that might just fall off.That said, this YINYOO KBEAR BT5 works and presents a nice way to take your IEMs wireless, and that is a nice experience in and of itself. I like that it also has embossed controls so that you can navigate back and forth, and adjust volume just by feeling the surface of the control box.

This product is great except for one failing. The TFZ style pins slip out of the earbud. I would not use it for exercise, but for listening to music while I work, it is excellent.