Lock washers known as split lock washers place tension against a nut after tightening to help prevent the nut from loosening. Ideal for situations where potential loosening from corrosion or vibration is a concern. Lock washers provide a locking spring action and are used to prevent nuts and bolts from coming loose from vibrations. They have split ends that help "lock" into the mating material, thus providing a locking feature when tightened beneath a nut. Hot dipped galvanized finish provides one of the highest degree of corrosion resistance when compared to a steel zinc finish. Ideal for outdoor projects such as decks, fences, wood structures and with treated lumber installations.