EFSR-GFI Series 1-Gang Ground Fault Circuit Interrupter, Voltage Rating: 125 VAC, Amperage Rating: 20 AMP, Frequency Rating: 50 - 60 HZ, Trip Type: 5 MILAMP Trip Setting, Enclosure: NEMA 3, 3R, 7BCD, 9EFG, Material: Cast Copperfree (Less Than 4/10 Of 1 PCT) Aluminum, Finish: Baked Gray Epoxy Clad, Mounting: Surface Mount With 3/4 IN Feed-Thru Hub, Standard: Class I, Group B, Class I, Groups C, D, Class II, Groups E, F, G, Class III, UL Listed: E81751, UL Standard: 943, 1203, For U-Line 20 AMP Receptacles