These steel nipples are plated in a zinc finish. They are made primarily for lamp repair or construction. Each nipple is 1 inch long and has an exterior (male) thread the entire length. The nipple measures 3/8 inches OD and has an 7mm (slightly more 1/4 inch) hole from one end to the other so that you can push a lamp wire through it. The thread is designated 1/8 IP which is standard lamp threading. This offer includes 100 of these useful lamp-making accessories.