A flat washer is a simple, disc-shaped piece of hardware used to distribute the load of a fastener, such as a screw or bolt. It is typically made from materials like metal, plastic, or rubber and comes in various sizes. Flat washers help prevent damage to the surface being fastened and can also reduce friction. These washers are commonly used in construction, automotive, and machinery applications. By providing a smooth surface, they help ensure a secure fit and can also assist in preventing loosening due to vibration. Flat washers are often paired with other components like nuts and bolts for effective assembly.