Steel, cmpsn 4140, spec mil-s-5626 or steel, cmpsn 4340, spec mil-s-5000. In accordance with mil-std-171 finish will be black oxide for iron and steel, mil-c-13924. Class 1, alkaline oxidizing process (for wrought iron, plain carbon, low alloy steels). Length93.570 plus or minus .003. Width 1.385plus .001