1000 WATT DOUBLE ENDED R7S BASE HALOGEN LIGHT BULB - 254 MM LENGTH OR 10 1/16 INCHES - 120 VOLTS LONG LIFE - Supra Life tungsten halogen bulbs use a quartz envelope for durability and pure tungsten for longer life. The regeneration cycle continuously restores the filament, creating a 6 times longer burning life and clear crisp white light. Bulborama tungsten lamps are engineered to minimize heat and provide maximum energy efficiency.