In order to control the speed of ceiling fans, you can use capacitor speed controllers in addition to step transformers and speed controllers. They control hum-free in 4 Stufen.Design - plastic housing in white, with 4-step rotary switch and toggle switch.Function - 4-stage with off position. On/off switch for fan light. It is delivered with a surface-mounted housing. (Screws are included in the scope of delivery / bulbs are generally not included in the scope of delivery for fans.) Installation in standard flush-mounted boxes (single flush-mounted box) is also possible. Operation - The device uses microcapacitors for hum-free speed control. For the switching of motor and light, 2 separate phases (1x phase motor and 1x phase light) are needed. Version - Supplied with surface-mounted housing. Compatibility - Suitable for ceiling fans with a motor power of up to 150 watts and a current consumption of the lamp up to 400 watts.