Salco Products (TC1316PAH1) 1-inch Stainless Steel Plug with Stainless Steel Link consists of a plug that has 1-inch NPT threads, and is made out of 316 stainless steel material with 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 1/4-inch, 18-8 stainless steel, swivel link that is crimped around the plug.