Ceramalux HID Lamp, HPS 150W E39 ED23 1/2 U ALTO, 150 W, 55 V, 3.2 A, High Pressure Sodium Lamp, Single Contact Mogul E39 Lamp Base, ED-23 1/2, 14220 lm, 24000 hr Average Life, 17 CRI, 2100 K Color, Clear, 2.94 in Dia x 7-3/4 in L, 106 lm/W Efficacy, 400 deg C Bulb, 210 deg C Cap-Base, Standards/Approvals: ANSI S55 Specified, Applications: For general and street lighting