The material is made of high quality 10.9 grade alloy steel. Their surfaces are treated with black oxide, which has excellent corrosion resistance, firmness, wear resistance and low temperature resistance. Widely used in various precision machinery industries, classified instruments, meters, electronic products, household appliances, communication products, automobiles, locks, lamps, toys and so on. Specifications: Head Style: Button Head Quantity: 1080PCS Material: 10.9 Grade Alloy Steel Main Color: Black Package Included: M2 x 4mm (25PCS) M2 x 6mm (25PCS) M2 x 8mm (25PCS) M2 x 12mm (25PCS) M2 x 16mm (25PCS) M2 x 20mm (25PCS) M2 Nuts (150PCS) M2 Flat Washers (150PCS) Allen Key (1PCS) M3 x 6mm (20PCS) M3 x 8mm (20PCS) M3 x 12mm (20PCS) M3 x 16mm (20PCS) M3 x 20mm (20PCS) M3 x 30mm (20PCS) M3 Nuts (120PCS) M3 Flat Washers (120PCS) Allen Key (1PCS) M4 x 6mm (15PCS) M4 x 8mm (15PCS) M4 x 12mm (15PCS) M4 x 16mm (15PCS) M4 x 20mm (15PCS) M4 x 30mm (15PCS) M4 Nuts (90PCS) M4 Flat Washers (90PCS) Allen Key (1PCS) Package Quantity: Total: 1080 PCS, M2 M3 M4 Button Head Socket Cap Screws Nuts Flat Washers Assortment Set Warranty: Whenever you need us, please contact us by email or Q&A. We will provide you with professional services and reply to you as soon as possible. If you are not satisfied with the product, you can get a full refund, and you can buy it with confidence.