The micro:bit itself is a small device measuring 4 by 5 cm, but that small board is packed with features like a 5 x 5 LED display, a compass, accelerometer, two buttons, Bluetooth Low-Energy antenna which allows the micro:bit to interact with a smartphone or laptop. The micro:bit also has 20 GPIO (General Purpose Input Output) pins which can be accessed by the use of crocodile clips or by inserting the micro: bit into a special connector which you can find on various accessories like robots.