This Aurora SGU10 bulb is specifically designed for special SGU10 lampholders that prevent the insertion of standard inefficient GU10 halogen bulbs therefore promoting the use of energy efficient lighting. 40 Lumens per Watt output allows compliance with the Building Regulations Approved document L1A/B requiring the use of energy efficient luminaires in dwellings. The bulb lasts 10 times longer than an equivalent incandescant bulb (10,000 hrs). Suitable for use in Fire Rated Downlights. Liquid Mercury Free.