Advance Electromagnetic Fluorescent Ballast, Series: Standard, T12 Lamp, 20 W Lamp, 120 VAC, 0.54 A, 60 Hz Frequency, Pre-Heat Start, 20 deg F Minimum Starting, Total Harmonic Distortion: 10%, Power Factor: 0.83, 1 Lamp, Thermal Protection: Class P, Ballast Factor: 0.83, ANSI C82.1 Ballast Grade, Metal, 6.5 in L x 1.94 in W x 1.38 in H Dimensions