Instant Start T12 Ballast will accept up to 2 or 1 F96T12 to F48T12 lamps Accommodates multi-voltages from 120 to 277-volts, extra versatile for your unique projects High performance instant start electronic ballast is for all general fluorescent applications Instant start electronic ballast for long lamp starting cycles and low initial cost Mounting dimensions: 8.9-Inch L x 0.3-Inch W, Mounting slot set 0.3-Inch apart