Mechanics, DIYers, and repair technicians - this 280-piece copper washer assortment is exactly what you need to stop searching for that one right size! The kit includes 12 different sizes ranging from M5 up to M20, so you're covered for everything from small engine repairs to larger machinery. These aren't cheap steel washers - they're pure copper with a melting point of 1083°C, offering excellent electrical conductivity and thermal resistance perfect for automotive, marine, generator, and industrial applications. The sizes are clearly organized in a compact transparent case measuring about 6.89 x 3.93 inches, so you can see exactly what you have at a glance. Copper washers are essential for creating solid seals in high-temperature and electrical applications, and having this variety means you'll always have the right size on hand. Pro tip: use a magnet to separate them quickly since copper isn't magnetic. Whether you're working on car engines, boat motors, plumbing connections, or electrical projects, this assortment saves you multiple trips to the hardware store and the frustration of not having the specific washer you need. The quality feels professional-grade, and at 280 pieces, this kit will handle countless repair jobs before you need to restock.