Conform to: ASME B107.4. Made from chrome vanadium steel with a highly polished mirror finish. Made to American Federal Standards, giving higher torque therefore improved performance. The wrench will fit over the pipe to give a positive location on the nut. Can be used on hydraulic pipes, brake pipes etc. Contents 5/16" x 3/8", 3/8" x 7/16", 1/2" x 9/16" and 5/8" x 11/16".