Salco Products (TC025PA) 1/4-inch Carbon Steel Plug Assembly with Carbon Steel Single Jack Chain consists of a plug that has 1/4-inch NPT threads, and is made out of carbon steel material. The width across the flats of the head is .63-inch. Length of the thread is .47-inches with the overall length of the plug being .72-inches. Comes with a zinc plated carbon steel single jack chain assembly that consists of a 7/32-inch, zinc plated carbon steel, split ring that is held in place in the center of the plug head with a 3/8-inch #6, 18-8 stainless steel, drive screw, and is connected to a carbon steel single jack chain with a 15/16-inch, zinc plated carbon steel split ring at the end.