Features: These flat washers are made of red steel paper and have a tighter seal. It contains the 12 most commonly used copper gasket sizes. Suitable for home DIY, cars, ships, generators, machinery and factories and other engines. Instructions for use are enclosed. You can get a total of 600 flat washer combinations, all of which are packed in a sturdy box for easy storage and use. Package Includes: 600x Washers Specifications: Material: Red Steel Paper Weight: 176g Size(outer dia.X inner dia.X thickness) & Quantity: 10x5.5x0.8mm 160pcs 12x6.5x0.8mm 100pcs 16x8x0.8mm 60pcs 16x10x0.8mm 80pcs 19x12x0.8mm 40pcs 20x12x0.8mm 40pcs 22.5x14x0.8mm 20pcs 22x16x0.8mm 30pcs 25.4x17.5x0.8mm 15pcs 27x20x0.8mm 20pcs 32x22x0.8mm 20pcs 32x24x0.8mm 15pcs note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.