Varilight 2 way Single Slate grey Dimmer switch. For your safety, electrical products must be installed in accordance with local building regulations. If in any doubt, or where required by the law, consult a competent person who is registered with an electrical self-certification scheme.. Flat screwless profile dimmer switch with matt satin slate grey finish. 1 gang internal switch, ideal for controlling 1 circuit. 2 way switches make it possible to control the same light from 2 locations. Dimmer switch by Varilight.