These are the custom PCBs designed and manufactured specifically for this application. They are not strictly required but make it much easier to build PicoMemcard since you don't need to cut up another memory card and all the soldering pads are easily accessible. All you need to do is to solder the Pico/RP2040-Zero on top of the PCB using a soldering iron. The Raspberry Pi Pico or RP2040-Zero must