A hex bolt is short for hexagonal bolt.

Six-Sided Head: The hexagonal shape allows tools (like spanners, wrenches, or sockets) to grip the head from multiple angles, making it easier to apply high torque.

Threading: They can be fully threaded or partially threaded.

Materials: Commonly made from steel or stainless steel. Steel hex bolts are often graded (e.g., Grade 2, 5, or 8 in the US; Class 8.8 or 10.9 in metric) to indicate their tensile strength.