4 x 5W dimmable SMD LED GU10 lightbulbs. These bulbs feature a thermal plastic body and frosted lens, with a dimming range of 30% - 100% light output. These ultra bright bulbs are energy saving (only 5W) and they give equivalent light output to 50W halogen bulbs. dimmable GU10 LED bulbs are designed to operate with trailing edge dimmer switches. (Conventional leading edge dimmer switches will not operate these bulbs and may cause irreparable damage to the LED bulbs). Before ordering, please ensure that you have a compatible Trailing Edge Dimmer Switch, if in doubt please contact a qualified electrician. Colour Temperature: 6000K (Cool White / Daylight). Lumens: 400. Lifespan: 20,000 Hours. Beam Angle: 110°. Not suitable for use with a wall touch dimmer switch.