4 in square, 1/2 in raised, 20 A receptacle, 1.594 in industrial surface covers are used to attach a 20 A receptacle, 1.594 in device directly onto 4 in square boxes in a industrial setting. Garvin Industries 4 in square industrial surface covers allow for a quick installation of devices and switches to steel covers before they are mounted to the box. GARVIN® Cover, 1.594 in Diameter, 4 in Length, 4 in Width, Square Shape, 20 A Receptacle Cover, Surface Mounting, Steel, G60 Galvanized