Varilight dimmer switches gives outstanding performance and gives long life and these dimmers are designed to meet the latest European Safety Legislation. The standard dimmers are suggested for mains voltage lighting only, even though they can also be used on low voltage applications but the Intelligent (IQ) Dimmer is best suited for for 1-way circuits. When selecting a standard dimmer add up the wattages of the bulbs you wish to dim and choose a dimmer with a suitable maximum load rating. 1 way Rotary dimmers are used for mains incandescent GLS lamps, standard mains light bulbs, maximum load as specified on the dimmer. It can also dim GU10 or similar Hi Spot Mains Halogen lamps. There is a zero risk of damage when using the TouchRemote Dimmers in case of lamp failure and a dramatically improved lamp life. When the dimmer is used with quality low voltage transformers such as Varilight low voltage transformers (product codes: YT50L, YT70L, YT105, YT150, YT250) it can control them up to maximum load as specified on the dimmer. With other brands of low voltage transformers, it is recommend only to control up to 5 low voltage transformers per circuit, as long as the total load does not exceed maximum wattage stated on the dimmer. 1 Gang - 1 Way 1x400W Dimmer Stylish Modern Design - Quick and Simple Installation White Inserts Finish: Polished Chrome (HC1) Dimensions: 91 x 91mm