High Pressure Sodium HID Bulb, Bulb Base Type Mogul Screw (E39), Bulb Dia. 2 1/4 in, Bulb Housing Glass, Bulb Shape ED18, Color Rendering Index 20, Color Temperature 2100K, Lumens 50,000 lm, Light Technology High Pressure Sodium, Overall Length 9 3/4 in, Shatter- No, Voltage 115V, Watts 401.5 W, Bulb Beam Angle 360 Degrees , Bulb Finish Clear, Rated Life 24,000 hr, ANSI Code S51, Dimmable No, For Enclosed Fixtures Yes, Bulb Operating Position Universal Burning