Hexagon socket head cap screw with internal and external teeth Specification: M8 Maximum outside diameter: 12.5 mm Minimum outside diameter: 10 mm Seal diameter: 14 mm Excellent Quality: These insert nuts are made from a large number of galvanized carbon steel materials, which provide strength and good corrosion resistance in many environments. Easy to use: These are multi-functional threaded nuts, you can easily use them to drive, easy to use. Features: Recessed nuts are better than barrel nuts and T-shaped nuts because they can be installed on one side of the room. Note: The depth of the pre-drilled hole should be as deep as the length of the inserted nut and any part of the bolt that can be screwed into the workpiece through the end of the nut.