An externally threaded fastener with metric threads, a cylindrical head with a flat chamfered top surface, knurled cylindrical sides and hexagonal recess, made from alloy steel.

Class 12.9 socket cap screws are comparable, but not exactly equivalent to U.S. alloy steel socket cap screws. Ideal for precision assembly work with close tolerances and applications needing a well-tooled appearance. Supplies greater tensile strength than equivalent sizes of Class 8.8 or 10.9 hex head cap screws while requiring less surface area or conterbore since the fastener is internally wrenched.