Steel, fed standard 66, aisi 1020 to 1030, phosphate, mil-p-16232, 1.250 in.Width, 1.125 in. Thick, 4.875 in. Lg, 0.625 in. Wrenching size at eachend, 0.754 in. Drive size in center, case harden 0.005 to 0.010 deep, rockwell 15n 89 to 91, each end will be on 2.4375 in. Radius