Advance Electromagnetic Fluorescent Ballast, Series: Standard, T12 Lamp, 20 W Lamp, 120 VAC, 0.47 A, 60 Hz Frequency, Pre-Heat Start, 20 deg F Minimum Starting, Total Harmonic Distortion: 10%, Power Factor: 0.9, 2 Lamps, Thermal Protection: Class P, Ballast Factor: 0.9, ANSI C82.1 Ballast Grade, Metal, 9.5 in L x 2.38 in W x 1.5 in H Dimensions