The end marked I is for power on, and the other marked O is for power off.
1x4 Pin Connector
It can export pins like P1, P2, 3V, GND. We can use it to do some extensions.
Two CR2025 Battery Sockets
You can place two 2025 batteries（or 3V button battery）into the socket.
The buzzer is controlled by P0 port.
Fix micro:bit onto power:bit with 5 screws. Then place a pair of 3V 2050 battery into the battery socket of power:bit. When we slide the switch to the end marked I, the whole device is powered on. When we slide the switch to the end marked O, the whole device is powered off.