Kit sizes: hex head screws included: M3x10, M3x20, M3x30, M4x10, M4x20, M4x30, M5x10, M5x20, M5x30, M6x10, M6x20, M6x40. 120 screws, 120 nuts, 140 spring washers, 140 washers. 520 pieces in total. 304 STAINLESS STEEL: The hex bolts are made of high quality and durable 304 stainless steel with excellent corrosion resistance, heat resistance, cold resistance and high toughness. EXQUISITE CRAFTSMANSHIP Our well-engineered nuts and bolts are the perfect pair for excellent results. And the wire is smooth, sharp and burr-free. Well Organized: All screws and accessories are organized in a sturdy plastic box with compartments, making it easy to find the parts you need. WIDE APPLICATION: Our assortment of M3 m4 m5 m6 bolts, nuts and washers are suitable for indoor and outdoor use, home and work, construction, furniture, automotive, bicycle, ship assembly and more Again.