Instant Start T8 Ballast will accept up to 1 F32T8 lamp Accommodates multi-voltages from 120 to 277-volts, extra versatile for your unique projects Instant start electronic ballast for long lamp starting cycles and low initial cost High performance instant start electronic ballast is for all general fluorescent applications Mounting dimensions: 8.9-Inch L x 1.1-Inch W, Mounting slot set 0.3-Inch apart