SignPRO, Electronic, Sign Ballast, Number of Bulbs Supported 4, Ballast Bulb Type T8HO, T12HO, Max. Bulb Watts 137 W, Min. Starting Temp. -20 Degrees F, Min. Total Bulb Footage 10 ft, Max. Total Bulb Footage 40 ft, 14 5/16 in Length, 3 3/16 in Width, 1 3/8 in Height, Input Watts 348 W, Voltage 120/277V AC, Standards CSA Certified, FCC Part 18, RoHS Compliant, UL Listed