Premium MaterialThe inner teeth quick release metal washers are made of 65 manganese steel. It is sturdy and durable, no deformation, abrasion resistance and corrosion resistance. Durable for a long time. A Starlock Washer exerts a spring force between the head and the substrate. Practical Tool Self-locking washers are ideal for quick fixes and repairs. It can apply spring force between the mounting head and the substrate, making the washer hard against the substrate. For greater resistance to friction and rotation. Various sizes Lock Washers with 7 most common sizes. There are M3/M4/M5/M6/M8/M10/M12 Starlock. You can choose different sizes according to your needs. Wide application Washer range widely used in many fields, e.g. machine equipment, lawn mowers, engines, cars, trucks, trailers, toys, bicycles, campers, boats, pumps, furniture, etc. Package Includes The Assortment Kit of fasteners contains 340 pieces of black color lock washer with a plastic box. Each size is individually separated in the storage box for easy selection and storage. 7 sizes of lock washers meet your different needs. Technical data - Product name: Lock washer - Material: 65 manganese steel - Color: black - Type: M3, 4, 5, 6, 8, 10, 12 - Thickness (M3, M4, M5, M6): 0.4 mm - Thickness (M8, M10): 0.5 mm - Quantity: 340 pcs Size: outer diameter x inner diameter: M3: 9 x 2.7 mm M4: 12 x 3.8 mm M5: 14 x 4.9 mm p> M6: 16 x 5.9 mm M8: 16 x 7.9 mm M10: 20 x 9.3 mm Height: M3: 1.4 mm M4: 1.5 mm M5: 1.5 mm M6: 2.1 mm M8: 2.3 mm M10: 2.3 mm Package contains: M3: 60 pieces M4: 60 pieces M5: 60 pieces M6: 50 pieces M8: 50 pieces M10: 40 pieces M12: 20 pieces Advantages: - The washers are made of 65 manganese steel, to be resistant to corrosion and durable. - A Lock Washer exerts a spring force between the head and the substrate, creating more friction and resistance to rotation. - These washers come in a divided storage box ideal for storage and removal. - Are widely used in machinery equipment, shock-absorbing industrial production, bearings, machinery, etc.