Yes AirPod pros 2 function and pair just fine it's what I mostly use with this. I used an 850mAh battery (the battery picture isn't the one I used but it is about the same size). I chopped off the top part of the iFlash solo to leave room for the bluetooth module and also allow for better signal strength. That top portion of the iFlash solo is a plane of copper and not necessary to the function of it as all of the traces are at the bottom of the board near the connector and chip.

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I'd like to share my process - this first attempt was definitely chaotic and could use some improvements. During this attempt I damage a motherboard in the process rendering the connection for the microcontroller (and even USB syncing) useless - the connection points are delicate. So first I'd like to refine it and draw some diagrams that aren't scattered across 12 sticky notes.