Power input: black DC jack (DC 7-9V) or micro USB port (DC 5V)
Voltage output: select 3.3V or 5V via jumper cap V1/V2
Comes with a power indicator
Extends the PIO of micro:bit into 3PIN interface
Serial communication pin
I2C communication pin
SPI communication pin
Dimensions: 65mm x58mm x12mm
Weight: 31g
WIKI page tutorial