A switch model that became common in Europe from the 1930s onwards. Made of white bakelite-like plastic. Turned on and off by a knob. Intended for surface mounting and therefore a special wall plate is also available as an option.

Staircase switch. “Staircase switch” means that you can turn the light on at one end of a staircase or room and turn it off at the other end. If you want a staircase switch, you need two switches with a so-called staircase function. If you want to be able to control the light from a third switch, this switch must have a cross function.