Ceramalux HID Lamp, HPS 100W E39 ED23 1/2 U ALTO, 100 W, 55 V, 2.1 A, High Pressure Sodium Lamp, Single Contact Mogul E39 Lamp Base, ED-23 1/2, 8460 lm, 24000 hr Average Life, 18 CRI, 2100 K Color, Clear, 75 mm Dia x 196 mm L, 94 lm/W Efficacy, 400 deg C Bulb, 210 deg C Cap-Base, Standards/Approvals: ANSI S54 Specified, Applications: For general and street lighting