Specifications Material:Steel High-concerned chemical:None Thickness(mm):0.3-1 is_customized:Yes Model Number:Push-on locking washers fasteners DIY Supplies:Metalworking Brand Name:JARBLUE Origin: China Certification:CE Thickness(mm):0.25~0.45mm Product description SpzcdZa 260-Pcs High Quality 65Mn Metal Steel Internal Tooth Starlock Washers Assortment Kit Specifications Washer Type: Starlock Washer Sizes: M3 M4 M5 M6 M8 M10 M12 Material: 65Mn Metal Steel Color: Black Features Made of 65Mn Metal Steel, Anti-corrosion and Durable A Lock washer exerts a spring force 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. These washers create a permanent installation and will lock on plastic, steel etc. This set is organized by size / type in a transparent storage case for quick access and protection. Package Included M3 - 50pcs M4 - 50pcs M5 - 40pcs M6 - 40pcs M8 - 30pcs M10 - 30pcs M12 - 20pcs Package Quantity: 260pcs