The hex bolt ,commonly known as hexagon bolt , is a fundamental and versatile mechanical fastener characterized by its six-sided (hexagonal) head and an externally threaded shaft.

A Flange Bolt is a specialized type of fastener that integrates a non-threaded, circular flange (or washer-like bearing surface) directly beneath the bolt head. This design combines a standard hex or other drive head with a built-in load distribution feature.

The allen bolt ,commonly known as hex socket head cap screw or hex socket head cap screw , is a versatile fastener distinguished by its cylindrical head with a hexagonal (hex) internal drive.