Conduit Outlet Box, Type GR, Explosionproof, Dust-Ignitionproof, Malleable Iron, Unilet, GRLB Hub Type, Internal Ground Screw and O-Ring, Internally Threaded Surface Cover with 3.38 Inch Opening, 18 Cubic Inches and (2) 1 Inch Threaded Hubs, For Use With Threaded Metal Conduit