Lock washer exerts a between the fasteners head and the substrate, which maintains the washer hard against the substrate and the bolt thread hard against the nut or substrate thread, creating more friction and resistance to rotation. Features -Color: Silver. -Material: Stainless steel. -Size: About 1.80X1.80X0.10cm/0.71X0.71X0.04in. -Specification Size: 3; 4; 5; 6; 8; 10. - With simple design and good working performance, it can play an excellent fastening role. - It can be used for fastening and buffering, and can be well used for replacement and maintenance. - Internal serrated lock washers are mainly used for small parts, which can effectively prevent loosening. - It can be widely used in most types of machinery and has good adaptability. - The scientific structure design makes it possible to prevent the nut or bolt head from loosening due to the action of the tooth strut. Package list: 300 x Washers