Description: Made of stainless steel washers, durable and strong, rust resistant, long lasting. These washers help to prevent bolts or nuts from pulling through a surface. Fitment: home, automotive, and shop use. Includes 6 sizes common use flat washers: 120 pieces M4,100 pieces M5,80 pieces M6, 50 pieces M8, 30 pieces M10, 15 pieces M12. Specification: Size: Approx. Inner diameter x Outer diameter x Thickness M4: 4x9x0.8mm/0.12x0.35x0.03inch; M5: 5x10x1mm/0.20x0.39x0.04inch; M6: 6x12x1.6mm/0.24x0.47x0.06inch; M8: 8x16x1.6mm/0.31x0.63x0.06inch; M10: 10x20x2mm/0.39x0.79x0.08inch; M12: 12x24x2.5mm/0.51x0.94x0.10inch; Package Includes: 120 pieces M4 flat washers 100 pieces M5 flat washers 80 pieces M6 flat washers 50 pieces M8 flat washers 30 pieces M10 flat washers 15 pieces M12 flat washers