This is an OSRAM EFR MR16 150 watt HLX bulb with a base of GZ 6.35 2-Pin. These bulbs are most commonly used for stage and studio lighting, specialty lamps, and industrial lighting. The maximum overall length of thins bulb is 1.653 inches. It has a rated life of 50 hours, a color temperature of 3350k, and a filament of C-8.