A nipple is a short piece of pipe with male pipe threads at both ends. It is used to join two female threaded steel pipes. The length of the nipple is specified by the overall length including the threads. A "close nipple" has no unthreaded area and is virtually unexposed when connected to two female fittings.
Black nipples are manufactured of steel. They are commonly used for for steam and gas services. Common applications include steam boiler return lines and buried oil tank oil lines. Black pipe nipples should not be used for water, instead you should consider galvanized steel or PVC.
We offer a wide selection of Boshart black nipples in sizes from 1/8" to 12" in diameter and 1-1/2" to 72" in length.