GE Mercury Vapor Lamp, High Intensity Discharge, HR175DX39 Designation, 175 W Wattage, Mercury Vapor Lamp, E39 Mogul Screw Lamp Base, ED28 Shape, 7800 Lumens, 20000 hr Average Life, Deluxe White, 50 CRI, 3900 K Color Temperature, Deluxe White Lamp, Open/Closed Fixture, 3-1/2 in Dia x 8-1/4 in L