A hex bolt is a type of fastener that has a hexagonal head and a threaded shank. The hexagonal head is designed to be tightened and loosened using a wrench or pliers, allowing for a secure and adjustable joint. Hex bolts are commonly used in construction, machinery, and automotive applications, as well as in DIY projects and general hardware applications. They are available in a range of sizes, lengths, and materials, including steel, stainless steel, and brass.