Hilitchi 510Pcs M4/5/6 Stainless Steel Metric Hex Flat Head Bolts Screws Nuts Flat and Lock Washers Assortment Kit High Quality 304 Stainless Steel Hex Head Screw Nut Washers Assortment Kit. Products include: Metric Hex Flat Head Bolts Screws, Nuts, Flat and Lock Washers. Different Size of M4, M5 and M6. Package Quantity: 510Pcs, All of screws will be packed in a sturdy plastic box, can be use for a storage box Material: 304 Stainless Steel (Not 201 Stainless Steel), Very Good Corrosion Resistance, It Can Be Used in a Humid Environment.