Advance Electromagnetic Fluorescent Ballast, Series: Standard, 40 W Lamp, 277 VAC, 0.36 A, 60 Hz, Instant Start, 50 deg F Minimum Starting, Total Harmonic Distortion: 25%, 2 Lamps, Thermal Protection: Class P, Ballast Factor: 0.96, Metal, 9.5 in L x 3.11 in W x 1.78 in H