This Philips Genie Energy Saver Bulb is an 11W CFL bulb that provides the equivalent light output of a 60W incandescent bulb. It features a Bayonet Cap (BC) [B22] fitting and produces a warm white light at 2700K. The bulb is approximately 113mm high and 45mm wide. Energy saving lamps, also known as compact fluorescent lamps (CFLs) or low energy bulbs, use technology similar to fluorescent tubes to generate light. This results in significantly lower power requirements and a much longer life expectancy compared to conventional tungsten filament bulbs. The marked wattage of all energy-saving lamps is considerably lower than the equivalent conventional bulb, leading to lower running costs. This bulb is 'A' rated for energy efficiency and has an estimated lifespan of 10,000 hours. A VAT invoice is dispatched with the goods.