Salco Products (TC1N60P1AH) 1-inch Nitronic 60 Plug Assembly with Seal Hole and Carbon Steel Chain consists of a plug that has 1-inch NPT threads, and is made out of Nitronic 60 material with a 9/32-inch seal hole drilled through the head. The width across the flats of the head is 1-3/8-inches. The length of the thread is 1-1/32-inches with the overall length of the plug being 2-1/32-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.