175-watt High-Intensity Discharge (HID) Quartz Metal Halide light bulb featuring an elliptical BD17 shape and an E26 medium screw base. This lamp requires a standard M57 ballast to operate and is strictly rated for use inside enclosed fixtures only due to its unprotected arc. Wattage: 175 Watts Base Type: E26 Medium Screw Base (1-inch diameter) Bulb Shape: BD17 / ED17 (Elliptical)Brightness: 13,600 Initial Lumens (approx. 8,800 Mean Lumens) Color Temperature: 4000K Cool White / Daylight White Burn Position: Universal Burning Position Rated Lifetime: 10,000 Hours (Vertical) / 6,000 Hours (Horizontal)ANSI Ballast Code: M57