(case of 10) GE 85857 GETR277/120-175W LFL ProLine Magnetic Core & Coil Ballast. LFL ProLine Magnetic Core & Coil Ballast. Case of 10 ballasts. Precision-wound coils, ensuring even heat dissipation and the highest electrical integrity. Internal Auto Reset Thermal Protector Rated 100C. For use on single phase. Non-Isolated Autotransformer designed specifically for lighting applications to step down 277V to 120V. For use with one or more electronic 120V or universal voltage ballasts within max total system power of autotransformer. 277V rms Input, 60Hz Only, 120Vrms Full Load Output. For loads with total system power. 277Vrms Input, 60Hz Only, 120Vrms Full Load Output. Length 9.5 inches; Width 1.7 inches; Height 1.2 inches.