Advance Electromagnetic Fluorescent Ballast, Series: Standard, 85 W Lamp, 120 VAC, 2.4 A, 60 Hz, Rapid Start, -20 deg F Minimum Starting, Total Harmonic Distortion: 0.3, Power Factor: 0.98, 4 Lamps, Thermal Protection: Class P, Ballast Factor: 0.92, Metal, 11.75 in L x 3.19 in W x 2.63 in H