SPECIFICATION: NEMA 6-50R receptacle, 50amp 250V, Accepts cord size up to 4AWG, designed for welding. The Welding Power Outlet box is ETL certificated, built to last CONVENIENCE: Heavy duty box,it can be installed indoors and outdoors for the convenience of your welding work.The box prevent the outlet from dust, water and other elements GREAT DESIGN: There is enough space for close the lid while plugging the cord even with a big handle. lid can be positioned to stay up while working with the box.Knockout Hole by using knockout punch kit, multiple punching locations for you to choose LOCKABLE: CAMPER MATTERS power outlet box elevated cover with padlock prevents unauthorized use. Anti-theft lock enclosure. WIDE USE: Perfect for application of high amperage industrial and commercial power connectivity