Salco Products (TC3PA) 3-inch Carbon Steel Plug Assembly with Carbon Steel Chain consists of a plug that has 3-inch NPT threads, and is made out of carbon steel material. The width across the flats of the head is 2-1/8-inches. Length of the thread is 1.38-inches with the overall length of the plug being 2.69-inches. Comes with a carbon steel chain assembly that consists of a 1/4-inch, carbon steel, swivel link that is crimped around the plug, and is connected to a 1/4-inch, carbon steel, chain of 15 links with an approximate length of 19-inches.