280piece professional copper washer gasket set for sealing and load distribution across a wide range of hardware tasks. This assorted kit is designed for metric systems and covers sizes from M5 to M20, and it comes neatly organized in a sturdy storage box for easy access and quick selection. Key benefits Reliable sealing: copper washers compress to form a tight seal on threaded connections, helping to prevent leaks and ensure dependable performance. Load distribution: flat ring design spreads tightening force over a larger area to protect mating surfaces from damage and galling. Corrosion resistance: copper provides good resistance to corrosion in many common service environments, extending the life of seals and connections. Organization and accessibility: includes a boxed storage solution that keeps 280 washers neatly sorted by size for fast identification and retrieval. Versatility: suitable for a variety of hardware projects and tasks in plumbing, automotive, machinery, and general hardware applications. Key attributes Material: copper Type: washer gasket, flat ring seal Size range: M5 to M20 (assorted standard metric sizes) Quantity: 280 pieces Storage: durable box included Application: hardware accessories and general mechanical assemblies Compatibility and performance Designed to fit standard metric hardware with bolt/nut sizes from M5 through M20, making it suitable for many common , maintenance, and construction tasks. Copper's malleability helps achieve a reliable seal on softer mating surfaces while distributing load to minimize surface damage. The assortment covers a broad range of sizes, enabling precise selection for different fastener diameters and joint configurations. Use cases Plumbing connections: seal threaded water or gas fittings where a copper washer provides a dependable seal and reduces the risk of leaks. Automotive maintenance: seal oil or coolant lines where a copper washer can be used with compatible drain plugs, fittings, or flanges. General hardware assembly: distribute load on bolts and nuts in machinery, equipment housings, or flange connections to prevent surface damage and improve joint integrity. How to use Inspect mating surfaces and clean both surfaces before installation. Choose the washer size that matches the bolt or nut being used (M5–M20 range). Place the copper washer between the fastener and the contacting surface, ensuring full, even contact. Tighten to the appropriate specification for the application to achieve a proper seal without overtightening. Care and storage Keep washers in the included box to maintain organization and prevent loss. Store in a dry environment to preserve material integrity and ease of future use. Avoid bending or deforming washers beyond their intended flat shape to maintain sealing performance. This copper washer gasket set offers a practical, durable solution for sealing and load distribution across a variety of hardware tasks, backed by a specific size range (M5–M20) and a convenient storage box for easy organization.