Complete 3-piece socket that has bottom cap with 1/2" threaded hole (works with 1/4 IPS pipe). It turns on bottom light, top light (bottom light goes out), both come on simultaneously, then off. Large hole Bottom hole is threaded and 1/2"- works with standard 1/4 IPS pipe. ( Large Hole) These are polished gilt complete 2-circuit 3-terminal nite-lite lamp part socket to wire lamps. (It works, for example with a Gone-with-the-Wind hurricane lamp. It lights the top bulb, the bottom, then both, and off.) You get 1 shell, 1 cap, and 1 interior socket. (These are NOT 3-way or off-on sockets- works with nite-lite). Bottom hole is threaded and 1/2"- works with standard 1/4 IPS pipe. How to wire a "nite-lite" 3-terminal socket- specifically for a "hurricane" or "Gone-with-the-Wind" lamp. You can run all your wires up through the hollow pipe then screw bottom cap onto the threaded pipe. The cord should be a "2-wire"- one side is completely smooth and the other side has a subtle ridge. The nite-lite socket has 2 wires also- easily identified as "black" and white". Ribbed wire from cord with plug and white wire from nite-lite socket both attach to silver socket screw. The smooth wire on the brown cord attaches to the gold screw. The black wire from the nite-lite socket attaches to the black screw.