Metal Halide Lamp, 60, 4000 K, 31200 LM (Horizontal);39400 LM (Vertical) Brightness (Lumens), 400 W, Clear, Hard Glass Material, 15000 H (Horizontal);20000 H (Vertical) Average Life, E39 Mogul Screw Base, M135/M155 Ansi Ballast Code, Non Dimmable, 4.62 In Diameter, 11.5 In Height, 61.11 % Mercury Content, 4.45 LB