Electromagnetic TL ballast. Compatible with a wide variety of fluorescent bulbs including Preheat, Rapid Start, 2-Pin CFL, Slimline, High Output, Very High Output, and Circline. Starting Method: Preheat Wattage: 14W, 15W, 18W, 19W, 20W Voltage: 120V Number of Lamps: 1 Lamp Ballast Type: Magnetic Rapid Start