520pcs M3 M4 M5 M6 Kit Stainless Steel Hex Socket Body Socket Thread Bolts Screws with Nuts Assortment (520pcs Kit)Various Screw Sizes: M3*8, M3*12, M3*16, M3*20, M4*8, M4*12, M4*16, M4*20, M5*8, M5*12, M5*16, M5*20, M6*8, M6*12, M6*16, M6*20 to different ones to meet needs.It is a very essential hand tool for the family.With M3, M4, M5 and M6 nuts and washers, fasteners are now more precise with an increase in contact area, which reduces pressure and protects parts and screws.The nuts and washers are arranged in a storage box, making it easy for you to find your way through the series and avoid losing them in an emergency.They are antioxidant and corrosive even at high temperatures.The main use of stainless steel hex screw is very common in electronics, electrical appliances, chemicals, water, machinery and equipment, furniture and many other fields.