5 x 400w energy saving R7s Linear Halogen floodlight security light bulbs (equal to 500w), 118mm length , with even light distribution. 2800k. 860 Lumens. 1,000 hours average bulb life. Suitable for use with a dimmer switch. All MiniSun bulbs are quality tested to ensure maximum life and reliability. Use of different types and finishes of bulb can dramatically alter the mood and atmosphere providing bright light in working areas and soft tones in areas of relaxation. Halogens are energy saving and long life, lasting up to twice the life of ordinary GLS bulbs.