General description 280 pieces of high-quality spring washers made from 65 manganese steel, designed for quick locking applications. This set includes a variety of sizes to meet different needs, all conveniently packaged in a plastic box. Technical specifications Material: 65 manganese steel Quantity: 280 pieces Sizes: M3*9mm, M4*12mm, M5*12mm, M6*14mm, M8*18mm, M10*20mm, M12*25mm Plastic box dimensions: 9.5*17*2.2cm Color: Black Usage Ideal for various DIY and home improvement projects Provides a secure locking mechanism for bolts and screws