This four type washer set is designed to improve fastening reliability and protect joints in outdoor and indoor applications. - Spring washers (Federscheiben): The smooth surface reduces friction between fasteners, helps prevent loosening and dispersion, and enhances securing action. - Bolt washers: Corrosion resistant for outdoor use, easy to install, compatible with standard bolts and nuts, and works with spring washers for enhanced retention. - Stainless steel flat washers: Flat, reliable bearing surface to prevent pull through, distributes load, and supports secure fastening. - Lock washers: Each set contains many washers for long lasting use, reducing trips to the hardware store and providing spring locking action. Use scenarios - Outdoor deck, fence, or railing installations where corrosion resistance and secure joints are needed. - Machinery or automotive assemblies subject to vibration that can loosen fasteners. - Outdoor furniture or electrical enclosures that require durable, rust resistant fasteners.