Salco Products (TC1316PAH) 1-inch Stainless Steel Plug Assembly with Seal Hole and Stainless Steel Chain consists of a plug that has 1-inch NPT threads and is made out of 316 stainless steel material. It features a .281-inch seal hole drilled through the head. The width across the flats of the head is 1.38-inches. Length of the thread is 1.03-inches with the overall length of the plug being 2.03-inches. Comes with a stainless steel chain assembly that consists of a 1/4-inch, 18-8 stainless steel, swivel link that is crimped around the plug, and is connected to a 1/4-inch, 18-8 stainless steel, chain of 15 links.