1. Made of durable nylon, wear-resisting corrosion resistance.2. The nylon flat provides a bearing surface for fastener load distribution or is used as a spacer between components. 3. Nylon provides resistance to abrasion, corrosion, and many chemicals and solvents. The material is a strong yet lightweight plastic and is non-conductive.Specifications:Material: NylonThickness: 1mmInner Diameter: 4mmOuter Diameter: 10mmPackage Contents:50 x Flat Washers