The ANSI-certified and UL-listed unit has an aluminum buss and a rugged, heavy-duty, 100% galvanized-steel enclosure that is coated for durability. The CHU1N7N4NS has a 50A, 30A, and 20A receptacle. The item 50 Amp 3-Space 3-Circuit 120/240-Volt Unmetered RV Outlet-Box 50/30/20-Amp GFCI is in sale since Friday, March 10, 2017.