2-circuit 3-terminalinteriorsocket onlyto 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.). It has bottom hickey that has 3/8" threaded hole that works with standard 1/8 IPS pipe. Cardboard cover is included.Rated 250W and 250V. We combine with other items to save on shipping. $3.13 each.Shipping is $3.10 for 1 and $.38 for each additional piece.Combined shipping- to get the cheapest shipping cost (when buying different items) please buywhat you need and "request invoice" so we can send invoice with lower shipping costs."How to Request Invoice when using shopping cart"---From your eCRATER cart, near the top of the page, move your mouse curser over our name “lamppartsguy” and a drop down menu will appear with the option to request invoice from seller.