【Premium Material】The 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 Washers exerts a spring force between the head and the substrate. 【Practical Tool】The self-locking washers are ideal for quick fixes and repairs. It can apply a 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】The 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, RVs, boats, pumps, furniture, etc. 【Package Includes】The fastener assortment kit contains 340 pieces of black color lock washer with a plastic box. Each