A small USB dongle meant to help you connect to wifi or bluetooth devices.
EZ-Robots use WiFi to connect to computers. Some desktop computers do not have WiFi cards installed, and are instead hardwired to the internet. A WiFi dongle will help with that. Recommended 1 per robot if necessary.
A Bluetooth dongle can help connect to things such as a Wii remote. Some devices are compatible with EZ-Robots and EZ-Builder, and can be used to control the robots.