 It is the PAM 8302 Stemma Audio Amplifier. It's a mono 2.5 watt amplifier and it is pretty plug-and-play. You can see here I've got a little speaker here plugged into the screw terminal and then we have a little Stemma 3-pin plug that you can plug into your project and get the audio power and ground reference over to the board. So I'm just going to power this up over USB and see if I can adjust the volume down and up. It is the Max 8302 Stemma Audio Amp.