This fully dimmable 4.9W LED ST64 spiral filament light bulb is part of a wider range that has been developed by Crompton Lamps as a means of replacing its outgoing antique filament range. Each light bulb in the range delivers form and function equally with the same gorgeous, retro styling no longer stymied by the restraints of outdated filament technology. The tungsten filaments found in these older light bulbs have given way to two spiral LED filaments, resulting in a gorgeous, traditional aesthetic that belies the light bulb's ultra-modern specification. These filaments, albeit similar in appearance, are much more efficient and robust than their traditional counterparts. Where a traditional light bulb might use approximately 25W to produce 400 lumens, these modern LED light bulbs use just 4.9W. This - coupled with the light bulb's vastly superior nominal lifetime of 15,000 hours - has the potential to reduce lighting bills by up to 90%. The antique-bronze finish applied to this ST64 spiral filament light bulb lends it an extra warm white colour that really reinforces its vintage aesthetic, particularly when the light bulb is dimmed to lower levels. What are Antique Filament light bulbs? Elegant yet industrial, intricate yet masculine, antique filament light bulbs evoke the memory of Edison's early design and recreate the aesthetic of the Victorian age. Hung from the ceiling in exposed clusters or used in singular, shaded fittings, these light bulbs manage to be both simple and sophisticated with the raw beauty of the filament elevated to the fore of their design. Features a ES-E27 Edison screw (27mm) base/cap. Compatible with both leading and trailing edge dimmers*. For Indoor lighting use only. This LED ST64 light bulb is compatible with most dimmer switches, but please refer to the manufacturers website for an up-to date list of compatible dimmer switches.