Features: Made from nylon material, with a smooth surface, antioxidant and wear-resistant property, lightweight, and good insulation. Can be used for a long time. It can effectively serve as a supporting surface for the load distribution and wear resistance of fasteners. It has excellent insulation and corrosion resistance, and plays a protective and stable role. Durable and easy to install. Pack in a sturdy and clear storage box. Each size has clear labels. It is very convenient for you to choose the size, easy to carry and store. Widely used in mechanical equipment, mainly to reduce pressure and friction, prevent leakage, isolation, loosening or dispersion of pressure. Specifications: Material: Nylon Box Size: Approx. 13x6.5x2.3cm/5.12x2.56x0.90inch Total weight: 54.6g 2mm Size: Approx. 5x2x1mm/0.20x0.08x0.04inch 2.5mm Size: Approx. 5x2.5x1mm/0.20x0.10x0.04inch 3mm Size: Approx. 6x3x1mm/0.24x0.12x0.04inch 4mm Size: Approx. 8x4x1mm/0.31x0.16x0.04inch 5mm Size: Approx. 10x5x1mm/0.39x0.20x0.04inch 6mm Size: Approx. 12x6x1.2mm/0.47x0.24x0.05inch 8mm Size: Approx. 16x8x1.5mm/0.63x0.31x0.06inch 10mm Size: Approx. 20x10x2mm/0.79x0.39x0.08inch (Size=outer diameterxinner diameterxthickness) Note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 100pcs 2mm 100pcs 2.5mm 100pcs 3mm 50pcs 4mm 50pcs 5mm 50pcs 6mm 40pcs 8mm 10pcs 10mm