The LT series has a 277 V or 120 V primary to 12 V secondary and a common VA size of 50. The LT277-50-12 is ideal for 480 V, 3 phase 4-wire systems where line voltage to neutral is equal to single phase 277 V 50/60 Hz. The LT120-50-12 is designed for single phase 120 V 50/60 Hz supplies. This series has safety extra low voltage isolation that eliminates potential shock hazards. It is also constructed with corrosion-resistant half inch threaded mounting features with 18-gauge color coated wires. The 277 V and 120 V share common dimensions of 2.60 inches (66 mm) wide by 2.18 inches (55.3 mm) high by 3.10 inches (78.7 mm) in length, and a length plus width of 6.0 inches (152 mm) and a weight of 1.7 pounds (0.77 kg).