Lamp parts: 2-lite off-set switchless hard plastic socket with medium-based sockets with 6" leads. This has 3/8" nipplesthreaded holes top and bottom with set screws. Rated 660W and 250V.These are for medium-based or "regular" light bulbs.We combine with other items to save shipping. We sell for less in lots of 10- see our store.$4.44 each.Shipping is $3.36for1 and $.48 for each additional switch.Combined shipping- to get cheapest shipping costs (when buying different items)please buy what you need (WITHOUT SHOPPING CART) and “request invoice” (BEFORE YOU PAY)so we can send invoice with lower shipping costs.SHOPPING CART DOES NOT SEEM TO WORK FOR COMBINED SHIPPING.