Galvanized Flat Washers
The Galvanized Flat Washers is hot-dipped galvanized hardened steel. Designed to give a wider range to secure the nut from sliding through the bolt hole. The flat washer presses up against what the bolt is trying to secure. Flat washers sit flush against the wood or steel.
A washer is a thin plate (typically disk-shaped) with a hole (typically in the middle) that is normally used to distribute the load of a threaded fastener, such as a bolt or nut.