Micro: IO-BOX Expansion Board DFRobot Micro: IO-BOX Expansion Board is a micro:bit multifunctional expansion board with onboard Li-ion CR123A battery power. This CR123A is a 3.6V and 1000mA lithium rechargeable battery with a small size, high capacity, and high safety. The DFRobot Micro: IO-BOX has a 2-way driver motor, 9-way IO port, 2-way I2C port, 1-way serial port, 1-way buzzer, 4-way RGB LED, and a charging circuit. This expansion board is designed with a durable and indestructible outer protective cover. The Micro: IO-BOX employs a high-cost boost-buck power management solution that provides a stable power supply.