Advance HID Ballast, Magnetic, Metal Halide Lamp, 250 W Lamp, 294 W Wattage, 120/208/240/277 VAC, 2.6/1.5/1.3/1.1 A, 60 Hz Frequency, Probe Start, -20 deg F Minimum Starting, Power Factor: 0.9, No Dimmable, 1 Lamp, Thermal Protection: Class P, 71A5771 Lamp Base, Ballast Factor: 1, ANSI M58 Ballast Grade, 3.95 in L x 4.2 in W x 2.8 in H Dimensions