This is a new old stock chrome finish, 6" size adjustable wrench replacement Knurl wheel. This one will fit the older Crescent brand 6" wrenches that are marked Jamestown on them, and perhaps newer ones too. The thickness of the knurl is .44" long, and .44" diameter. Keep in mind that Crescent also made plain finish wrenches that were thicker in the jaw area, and had different gears, and threaded wheel (knurl), this one is for the chrome finish wrenches only. We will be listing replacement parts for several sizes of Crescent wrenches, as well as other brands. Ask us if you have any questions.