This is a bolt with a hexagonal head, widely used in many fields.
Hex bolts under the ANSI/ASME B18.2.1 standard are specified by the American Society of Mechanical Engineers (ASME), which defines dimensions, materials, and other requirements for hex bolts.
It is an inch-based thread standard originating from the United States, known as Unified threads.
Unified threads are classified into two types:
Coarse thread (UNC – Unified Coarse Thread) Fine thread (UNF – Unified Fine Thread)