What is the different between a steering wheel and a rim?

A steering wheel has their own circuit board, enabling it to provide a range of functionalities like buttons, rotary switches, REV LEDs, a display for telemetry data and so on. The steering wheel can directly mount onto a Fanatec Wheel Base.

A Rim is a single component lacking any electronic elements, and it needs always to be mounted on one of Fanatec's different hubs. It is important to note that a rim alone cannot use as a functioning steering wheel.