The Double Dimmer Switch, Cello is a two-gang dimmer plate in Cello, a soft citron yellow, with 3 knob shapes (Dot, Dip, Mum) and knob colours Carmine, Moss, Roma. Dimwit dimmers are made for 120V North American electrical systems, are single-pole only and work with most dimmable LED, CFL, incandescent and halogen bulbs.