Lamp, Shatter-Resistant, HID, HPS150 55/ALTO (PK X 12), 150 Watts, 55 Volts, 16000 Initial Lumens, 3 Amps, 2100 K, 21 CRI, ED23 1/2 Shape, 2.94 IN Dia, 7.75 IN Long, ED23 1/2 Bulb, Mogul (E39) Base, 24000 Avg Life Hrs, PFA Coating