These screws and nuts are made of 12.9 grade alloy carbon steel, which provides strength and is commonly used when requiring higher mechanical properties. There are many length compatible with your choice which can be commonly used in home and office appliance, machinery, furniture, repair and DIY inventions. Features: Made of 12.9 grade alloy carbon steel, which provides strength and is commonly used when requiring higher mechanical properties. Ideal compatible with use in confined areas where you need hex socket cap head screws. Fixing component, industrial and construction fasteners. 17 common sizes and different quantities that you can choose compatible with general purpose use. Used widely in the home and office appliance, communication equipment, ship assembly and other machinery industry. Specifications: Material: 12.9 grade alloy carbon steel Color: Black Type: Hex socket cap head Size:(optional) M3*4mm(fully-threaded) M3*5mm(fully-threaded) M3*6mm(fully-threaded) M3*8mm(fully-threaded) M3*10mm(fully-threaded) M3*12mm(fully-threaded) M3*14mm(fully-threaded) M3*16mm(fully-threaded) M3*18mm(fully-threaded) M3*20mm(fully-threaded) M3*22mm(fully-threaded) M3*25mm(fully-threaded) M3*30mm(partially-threaded) M3*35mm(partially-threaded) M3*40mm(partially-threaded) M3*45mm(partially-threaded) M3*50mm(partially-threaded) Quantity: 24pcs, 50pcs, 100pcs(optional) Package Includes: 1 Bag x Screws Note: 1. Please allow 1-2mm error due to manual measurement. Thanks compatible with your understanding. 2. Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.