General description Total 280pcs come with a transparent plastic case for sorting and storage. The washers are made of metal steel, which is corrosion resistant, high and low temperature resistant, and durable. The internal tooth star lock washers apply elastic force between the fastener head and the substrate to generate greater friction and anti-rotation. Technical specifications Material: Metal steel Sizes included: M3 (40pcs), M4 (40pcs), M5 (40pcs), M6 (60pcs), M8 (40pcs), M10 (40pcs), M12 (20pcs) Usage The internal washer kit is mainly used for various applications including appliances, lawn mowers, engines, tools, cars, trucks, trailers, electronic equipment, toys, bicycles, RVs, boats, pumps, and furniture. Other information Package Details: 40pcs M3mm washers, 40 washers M4mm, 40 washers M5mm, 60 washers M6mm, 40 washers M8mm, 40 washers M10mm, 20 washers M12mm, and 1 plastic box.