LOT OF 580 METAL WASHERS: This set contains 580 metal washers. They are all made of strong and durable stainless steel. Each set includes 9 kinds of most commonly used flat washers to meet all your needs. The size of these ranges from M2-M12 with several of the same size and their thickness varies between 0.3 mm and 2.2 mm. A plastic storage box is included with 9 compartments/sections to stay organized. 9 SIZES OF STEEL WASHERS: This high quality stainless steel washer assortment contains 9 different kinds of external, internal diameter and thickness. M2: 4.9 x 2.1 x 0.3mm; M2.5: 4.8 x 3.1 x 0.5mm; M3: 6.9 x 3 x 0.4mm; M4: 8.8 x 3.6 x 0.6mm; M5: 9.5 x 4.8 x 0.8mm; M6: 11x6x1.3mm; M8: 15 x 8.2 x 1.1mm; M10: 19 x 10 x 1.6mm and M12: 23 x 13 x 2.2mm. All these types of metal seal are sorted by compartments. A size guide is available on the lid. SOLID STEEL: The surface of this type of hinge washer is smooth, preventing you from getting injured when using it. Stainless steel is sturdy, strong and durable and won't break easily. It is also anti-rust and anti-erosion. Use this type of shim washer to distribute the pressure of fasteners like bolts and screws to protect the surfaces of the assembly parts. They also reduce friction, prevent leaks and won't come loose. MULTIPURPOSE: When not in use, store these flat washers in your box, lying on your shelf, in your box tool box or in a drawer. This set can be used at home, in a shed or at work.