Type: 100pcs M3, 100pcs M4, 100pcs M5, 50pcs M6, 50pcs M8, 20pcs M10, 10pcs M12, 10pcs M14, 10pcs M16, 5pcs M20 (Optional). Spring washers can prevent nut from automatic loosening, mainly used for occasions with vibration load or alternating load, tighten to prevent loosening.
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