Engineered to provide more uniform load distribution, split lock washers are great for any indoor/outdoor project. Ideal for situations where potential loosening from corrosion or vibration is a concern, split lock washers are used to prevent nuts and bolts from coming loose. These fasteners contain split ends that help "lock" into the mating material, thus providing a locking feature when tightened beneath a nut. The black ceramic finish offers superior corrosion resistance while conforming to the latest trends in hardware. Parts measure 3/8-in in diameter. Use with treated lumber in applications with like nuts and bolts of similar diameter.