Salco Products (TC2SPA) 2-inch Carbon Steel Plug Assembly with Square Head and Carbon Steel Chain consists of a plug that has 2-inch NPT threads and is made out of carbon steel material. The width across the flats of the head is 1.31-inches. Length of the thread is .88-inches with the overall length of the plug being 1.57-inches. Comes with a square head and 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.