Advance Magnetic Fluorescent Ballast, Series: SignPRO, T12HO Lamp, 110 W Lamp, 337 W Wattage, 120 to 277 V AC, 2.88 A, 50/60 Hz Frequency, Instant Start, Total Harmonic Distortion: 10%, Power Factor: 0.98, 4 Lamps, Ballast Factor: 0.61, ANSI C82.1 Ballast Grade, Metal, 14.31 in L x 3.19 in W x 2.63 in H Dimensions