They are commonly used for machinery and construction projects because of its sturdy structure. It's very suitable for applications with relatively large locking forces. Hex bolts can be used alone with a pre-threaded hole.
Material: 304 Stainless Steel 18-8 that you will probably see in home and workplace. It's used for a wide variety of home and commercial applications. Because of its slightly higher strength and wear resistance than type 316, it's also used for nuts, bolts, screws and other fasteners.