The IDM250 In-Line Dimmer has been designed to allow for multi-point dimming of your lights, which works by converting a retractive switch or toggle into a dimmer module with a neutral position. By holding the retractive switch down you can control the brightness of your lights, and with a simple click you can turn your lights on and off, allowing you dimming control from multiple switches. Please note that you only require one dimming toggle switch per circuit, for the other switch locations on the circuit, please use two-way standard retractive switches.