Metric hex head bolts are used to secure an object within or against another object. Bare metal fasteners have no corrosion resistant qualities and are a good choice for indoor and industrial applications. Property class: 10.9. Tensile strength 1040 MPa or about 150,000 p.s.i., similar to SAE grade 8. Head marking 10.9. Made from alloy steel, quenched and tempered. Used in construction, machinery, automotive repair and other projects by contractors, designers, OEMs, and maintenance staff for critical joints and high stress applications.