HID Bulb, Bulb Base Type Mogul Screw (E39), Bulb Dia. 1 17/20 in, Bulb Housing Glass, Bulb Shape ET18, Color Rendering Index 22, Color Temperature 2100K, Lumens 50, 000 lm, Light Technology High Pressure Sodium, Overall Length 9 3/4 in, Shatter-Resistant No, Voltage 100V, Watts 400 W, Bulb Beam Angle 360 Degrees, Bulb Finish Clear, Rated Life 24, 000 hr, Dimmable No, For Enclosed Fixtures Yes, Bulb Operating Position Universal Burning, Standards 2-15/64 in, Trade Number LU400/ECO, High Output Yes