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