GE Lighting 74119 GETR480/277-250W 480/277-Volt ProLine Magnetic Fluorescent T5 For use with one or more electronic 277-volt or universal voltage ballasts Precision-wound coils ensures even heat dissipation and the highest electrical integrity Features internal auto reset function and has thermal protected rating of 100C (212-Degree Fahrenheit) Non-Isolated autotransformer specifically for lighting units to step down 480 to 277-volts Mounting dimensions: 8.9-Inch L x 1.1-Inch W, Mounting slot set 0.3-Inch apart