SOCKET: 4-PIECE, KEYLESS with UNO THREADS, GROUNDED

This is a grounded keyless 4-piece heavy brass socket with UNO threads and a ground screw, available in brass, dark antique brass, and nickel finishes. 

The ground wire goes through a hole in the underside of the cap. It wire goes through the hole into the ground outlet protruding from the outside of the cap. The ground outlet has a set screw to hold the ground wire inside it.