USB hub

The Raspberry Pi only has two usable USB ports, so once you've plugged in a mouse and keyboard you will have used them all up.

A powered USB hub allows you to at least double the number of USB ports, and also to run certain power hungry USB peripherals that reportedly need a hub to work with the Pi.

Certain hubs have been found to cause the Pi problems but a list of hubs that are verified as working with the Pi can found here.

Photo: Nick Heath/TechRepublic