1. Power indicator
Powered on the, the indicator light will be red, no power it won’t light up.

2.P0 buzzer jump cap
The jumper cap IObit is plugged in by default. In the Makecode, you can use the music column to program, and make a sound. Usually, there is no sound when you power on.

3.3Pin IO port leads
All the pins in the have been taken out without any reservation (PS: there is no P17 and P18, not the IObit is not taken out)

4.40P Horizontal Socket
Compact size socket

5. Board mounting holes and fixing holes
The outermost two holes are approximately 4.8 mm in diameter and are compatible with Lego friction pins with a spacing of 48 mm.
The innermost two holes are about 3.1mm in diameter and can be tightened with ordinary M3 screws. The spacing is about 32mm.