This is a new old stock chrome finish, 12" size adjustable wrench replacement jaw. This one will fit the older Crescent brand 12" wrenches that are marked Jamestown on them, and perhaps newer ones too. The thickness of the jaw is .44" at the narrowest tip of the jaw, and the gear area diameter is .375". Keep in mind that Crescent also made plain finish wrenches were thicker in the jaw area, and had different gears, and threaded wheel (knurl). We will be listing replacement parts for several sizes of Crescent wrenches, as well as other brands. Ask us if you have any questions.