Hex head cap screws are used to secure an object within or against another object. Zinc plated fasteners have good corrosion resistant qualities and are a good choice for indoor and industrial applications. Grade 5 fasteners are heat treated and are stronger than grade 2 fasteners. They are used by contractors, designers, OEMs, automotive repair and maintenance staff for critical joints and high stress applications. Tensile strength: up to 1" - 120,000 p.s.i. (min). Three radial bars head marking. Made from medium carbon steel.