This Electronic Ballast features an energy-efficient design and rapid-start, quiet operation. This ballast is designed for use with 3 ft. and 4 ft. T12 lamps and can be used as a replacement for the 2-lamp. The ballast also features Linear fluorescent design series wiring rapid-start, energy-efficient, 2-lamp design for use with 3 ft. and 4 ft. T12 lamps.