GE 99651 GE254MVPS90-FT5 120/277-Volt UltraStart Electronic Fluorescent T5 Programmed Rapid Start Ballast 2 or 1 - F54T5HO Lamp Programmed Rapid Start T5 Ballast will accept up to 2 or 1  F54T5HO Accommodates multi-voltages from 108 to 305-volts, extra versatile for your unique projects High efficiency T5 ballast with continuous cathode cutout Technology Unit features auto-restart function, end of life protection, universal protection Mounting dimensions: 11.1-Inch L x Mounting slot set 0.25-Inch apart