HIGH QUALITY STEEL: These flat washers are made of Zinc Plated Alloy Steel, which is one of the highest forms of corrosion-resistant steel, allowing it to last longer than other hardware on the market today. WASHERS YOU CAN COUNT ON: Our hardware is very strong and is great for both indoor and outdoor use. Zinc Plated Alloy Steel is superior to ordinary steel and provides excellent rust resistance in wet applications. GREAT TO KEEP: Bolt Dropper hardware is ideal for use in wood and wet environments. They are strong, corrosion-resistant, and will help you with all your projects. SECURE HOLD - Trusted flat washers to prevent pulling. Our washers provide a flat bearing surface that distributes weight and provides a secure hold. Material: Steel . S Flat washers prevent bearing surfaces from being dented The washer not only protects the component's bearing surface from damage caused by tightening screws or nuts, but also allows it to be mounted on already damaged bearing surfaces.