Hex head bolts have a hexagonal shaped-head and a machine thread. Minerallac Company's hex bolts are available in a multitude of sizes, styles and finishes to suit a variety of applications. We offer bolts in varying grades to meet the majority of code requirements. Grade 2 are the most common and economical bolts. Grade 5 and Grade 8 are required in some applications where the load, sheer and/or tensile strength is important. The best way to specify the varying grades is by looking at the markings or lack of markings on the head of the bolt.