You the knob you turn on the dimmer to regulate brightness and darkness. The WarmDim lamp with energy-saving LED technology also dims the light colour infinitely between 2,000 Kelvin (gold light) and 3,000 Kelvin (warm white light). You can alter the mood at home however you like. Whereas warm white ambient light is generally best during the day, you can dim the light to golden for relaxed hours in the sofa or in the bath. You can screw the lamps into a wide variety of luminaires and use commercially available dimmers with most of them.