Function: 1 [Multiple Sizes] 7 most common sizes are available in M3, M4, M5, M6, M8, M10, M12, convenient and practical to meet your daily needs 2. [Locking Effect] Lock washer applies spring force between the machine head and bottom plate, securing the hard washer to the hard bolt screw on the front of the bottom plate to increase friction and rotational resistance 3.3. [Widely Used] Widely used in the field of mechanical equipment, electronics, home appliances and so on, suitable for craftsmanship, professionals, industrial, artisans, and decoration4. High Quality Carbon Steel: Made of high hardness and high quality carbon steel with excellent abrasion resistance. 5. [Easy Organization] Each size is divided into a storage box for easy access and storage Specifications: Item Type: Starlock Washers Product Model (Inner Diameter x Outer Diameter): M3x9mm; M4x12mm; M5x12mm; M6x14mm; M8x18mm; M10x20mm; M12x25mm Material: Carbon SteelPackage List: 120xM3 Washers 0 xM4 Washers 120 xM5 Washers 100 xM6 Washers 100 xM8 Washers 80 xM10 Washers 40 xM12 Washers