Advance HID Ballast, Enclosed Magnetic, Metal Halide Lamp, 400 W Lamp, 458 W Wattage, 120/208/240/277 VAC, 3.5/2/1.75/1.5 A, 60 Hz Frequency, Probe Start, -40 deg F Minimum Starting, Power Factor: 0.9, 1 Lamp, 78E6091 Lamp Base, Ballast Factor: 1, ANSI M59 Ballast Grade, Metal, 14.4 in L x 7.7 in W x 5.8 in H Dimensions