Hex bolts are one of the most common fasteners and can be used in a wide variety of applications. The 6 sided head makes them easy to install using a standard wrench or socket tool. Nuts and washers are not included, so will need to be purchased separately. Washers help to evenly distribute the load and should always be used under the bolt head and under the nut (just under the bolt head if installing into a threaded hole). Flat washers and finished/standard hex nuts work great for most applications, though if the bolt may be subject to excessive vibration, it is recommended that lock washers and lock nuts be used instead.