Galvanized 5/16 inch lock washers For general applications 5/16-inch inner diameter Galvanized finish with Rust-Oleum certified rust protection Use with nuts and bolts of the same inner diameter and finish

From the Manufacturer Used in applications with nuts and bolts. The split lock washer provides a more uniform load distribution. The split in the washers grips the material surface to prevent loosening during vibration. The called out size is the inner diameter of the washer.