We are offering spring washer. A split washer or a spring lock washer is a ring split at one point and bent into a helical shape. This causes the washer to exert a spring force between the fastener's head and the substrate.
We are offering plain washer. A plain washer or flat washer is a flat ring of steel used to spread the load of a screwed fastening. It may also be used when the hole is a larger diameter than the fixing nut.