FEATURES: Insert nuts are advantageous over barrel nuts and T-nuts because they can be installed on one side of the workpiece. GREAT QUALITY: These insert nuts are made from high quantity zinc plated carbon steel material which provides strength and offers good corrosion resistance in many environments. EASY TO TO USE: They are versatile threaded insert nuts that you can easily drive with them, easy to use. NOTE: The pre-drilled hole should be as deep as the length of the insert nut and any part of the bolt that can be screwed past the end of the nut into the workpiece. Note: The data is all measured manually, please allow 1-3cm error due to differences in light and display, there may be color differences, please refer to the actual item received .