GE UltraMax L electronic ballasts are a low watt option for maximum energy savings. With a ballast factor of. 77, the L line is the most energy efficient choice. The GE 78621 electronic fluorescent ballast operates (3) F32T8 lamps at 120/277 input volts. Ideal for use in low light areas, this instant start ballast is typically used in hallways, stairwells, and lobbies.