Plain washers, also known as flat washers, are essential components used in various applications to distribute the load of a threaded fastener such as a bolt or nut. These washers are typically made of metal or plastic and are characterized by their simple, flat, and circular shape. The main function of a plain washer is to prevent the nut or bolt from loosening, protect the surface from damage, as well as to reduce friction and wear. They are available in a wide range of sizes and materials to suit different requirements and are commonly used in construction, automotive, and industrial settings. Overall, plain washers play a crucial role in ensuring the stability and longevity of mechanical assemblies by providing a reliable and durable support system for fasteners.