The material is made of high quality 12.9 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. Specification: Thread Diameter 6 mm Head Diameter10 mm Head Height 6 mm Screw Length 60mm Allen Hex Drive5 mm High Quality Material 12.9 Grade Alloy Steel Package Included: 20PCS Socket Head Cap Bolts/Screws (M6 x60mm) 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