This is a Knightsbridge 2G 2 way leading edge dimmer with a 2 x 40-400W rating. With push on/ push off control. For controlling mains lighting add up the wattages of the bulbs you wish to dim. For low voltage lighting add up the rating of the transformers you wish to dim for compatibility. Made from high quality ultra slim, premium grade material Complete with integral gasket for moisture protection Minimum mounting depth: 25mm Dimensions: 87.5mm x 87.5mm Supplied in retail blister with full fitting instructions Compliant to BS EN 60669-1, BS EN 60669-2 15 year guarantee.