size: There are M6 M8 M10 M12 M14 M16 M18 M20 for you to choose to meet your different needs. Zinc plated steel: These coupling nuts are made of zinc plated steel with high strength and good corrosion resistance. good fasten performance: Used to fit bolts, studs or machine screws for fastening two parts together to make them one piece. hexagonal: Nuts adopted hex shape which has 6 sides that gives a good granularity of angles for a tool to approach from. Wide Applications: joint connector nuts are used in homes, offices, shipbuilding, communications equipment, and construction machinery. threaded bar nuts are also suitable for DIY projects like furniture assembly, model making, and metal construction, meeting a variety of practical needs, such as extending screws, connecting components, or installing washers.