For multi-location dimming, 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.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. With silent, flicker free technology, these Enkin dimmers come with a five-year guarantee, meaning you can be assured that your dimmer modules are the highest quality.