Size: We contain 500 pieces in the most popular and common sizes: 100 pieces M2 x 5 x 1 (model x outer diameter x thickness), 100 pieces M3 x 6 x 1, 50 pieces M4 x 8 x 1, 50 pieces M5 x 10 x 1, 50 pieces M6 pieces M6 pieces M6 x 12 pieces. 1.2, 4. 0 M8 x 16 x 1.4 screws, 10 M10 x 20 mm screws. Nylon Gasket: These black flat washers are made of soft and durable nylon, good insulation and strength corrosion-resistant, lightweight. These round washers are widely used in household appliances, electrical panels, sewer pipes, faucets, etc., pipes, generator sets, semiconductor, automobiles, ships and industrial fields. Function: The round spacer washer can be applied to disperse pressure from the bearing surface of the fastener such than the bolts to protect the surface of the connected part. In addition, it can reduce friction, prevent leakage, insulate, prevent loosening, etc. This anti-rust nylon flat washer assortment is easy to carry with a storage box, lightweight and sized different, ideal for DIY lovers, please make sure the size you want. Color: Black Delivered quantity: 500 pieces/set