Metal Halide Lamp, 65, 4000 K, 33100 lm (Horizontal);36000 lm (Vertical) Brightness (Lumens), 400 W, Clear, Hard Glass Material, 15000 h (Horizontal);20000 h (Vertical) Average Life, Mogul Base, M59 ANSI Ballast Code, Non Dimmable, 4.62 in Diameter, 11.5 in Height, 61.11 % Mercury Content, 4.45 lb