Flat washers, also known as plain washers, are the most basic and universal type. With a simple flat circular structure, they are mainly used to expand the contact area between the screw head and the assembly surface. In soft materials such as wood boards, plastic shells and thin metal plates, directly tightening screws will easily cause local pressure concentration, resulting in surface indentation, board cracking or hole deformation. Flat washers perfectly solve this problem by evenly dispersing pressure, protecting the product surface and filling uneven assembly gaps. They are suitable for almost all static assembly scenarios including furniture installation, electrical equipment and daily hardware connection.