Advance HID Ballast, Magnetic, Metal Halide Lamp, 250 W Lamp, 290 W Wattage, 120/208/240/277/480 VAC, 2.6/1.5/1.4/1.1/0.65 A, 60 Hz Frequency, Probe Start, -20 deg F Minimum Starting, Power Factor: 0.9, No Dimmable, 1 Lamp, Thermal Protection: Class P, 71A5750 Lamp Base, Ballast Factor: 1, ANSI M58 Ballast Grade, 4.75 in L x 3.1 in W x 4.25 in H Dimensions