1, 15 connect holes for 3V, GND and 9 I/O ports(include IIC and SPI), you can easily connect alligator clip lines. 2, Pin header connected all I/O ports, 3V and GND. 19 Red pin header terminals all connected 3V. 19 Black pin header terminals all connected GND. 19 Yellow pin herder terminals connected all I/O ports, P0 ~ P16, P19 and P20. 3, Total 24 positions screew terminal blocks, connected all I/O ports, 3V and GND. Terminal block pitch 3.5mm/0.138", wire size range 26AWG to 16AWG, strip length 5mm, screw M2 steel, pin header and cage copper. 4, Micro:bit officially recommended CYLCONN high quality card edge connector. FR-4 glass fiber PCB. High quality terminal blocks. 5, The item has been soldered and test passed. NOTE:the item not include Micro:bit module.