 It is the i2s amplifier BFF. Here you can see I have the i2s amplifier BFF soldered to the backside of a QT Pi RP2040, and then I've just plugged in one of these nice little speakers that have the picoblade connector so you can pull that right off depending on how your setup is is meant to be put together. This is playing three wave files that I have actually all playing at the same time and then I'm just changing their output levels in the mixer, in audio mixer. All happening inside of circuit Python, and they're just looping sounds. And you can see this will work really well for projects that are maybe small props, little enclosures, costume things, sound players, toys, little synthesizers, and the like. So really nice, easy, basically plug-and-play. It is the i2s amplifier BFF for QT Pi and Zhao.