Pull-Chain UNO Lamp Sockets are a simple style. They are brass with a metal interior. Wire exits thru base of socket-cap. Uno threads.
Brass Uno Lamp Sockets are controlled by pulling the connected chain. Pull chain is more convenient to use, with larger shades, as chain hangs down making it easier to reach than traditional on off switches. Lightweight lamps may need to be steadied when chain is pulled.
If using brass lamp socket with uno fitter shade: special uno threads, at light bulb-end of lamp socket, enable most lampshades and holders, with 1-1/4" threaded center ring, to screw directly on to socket.