580 PCS METAL WASHERS SET: This set contains 580 metal washers. They are all made of strong and durable stainless steel. Each set includes 9 types of the most commonly used flat washers to meet all your needs. They range in size 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 keep you organized. 9 SIZES OF STEEL WASHERS: This high-quality stainless steel washer assortment contains 9 types of different external diameter, internal diameter and thickness. M2: 4.9 x 2.1 x 0.3 mm; M2.5: 4.8 x 3.1 x 0.5 mm; M3: 6.9 x 3 x 0.4 mm; M4: 8.8 x 3.6 x 0.6 mm; M5: 9.5 x 4.8 x 0.8 mm; M6: 11 x 6 x 1.3 mm; M8: 15 x 8.2 x 1.1 mm; M10: 19 x 10 x 1.6 mm and M12: 23 x 13 x 2.2 mm. All these types of metal gaskets are sorted by compartments. A size guide is available on the cover. SOLID STEEL: The surface of this type of hinge washer is smooth, preventing you from being injured when using it.