Sylvania Metalarc BT37 1000-Watt Compact quartz metal halide lamp with a clear finish features a mogul base and has a universal operating position. Lamp with a CRI of 65 has an average life of 9000 hours and operates at a temperature of 3800 deg K. It measures 4.606 Inch diameter x 11.500 Inch. The initial brightness of the lamp is 110000 Volts and the mean brightness of the lamp is rated at 96000 Volts.