Okay, so this is called Tinybit Bluetooth controller and Microbit is the brain of Microbit. In Microbit there is LED, Button A, Button B, and sound, while in Tinybit there are 2 wheels, sensors, etc. In Microbit you can use Bluetooth and also can use cable, for tnybit there is ultrasonic sensor and tnybit can work but you have to use tnybit and have to code first and to use it you have to use a website called lofi or others