GREAT QUALITY: These insert nuts are made from a high quantity zinc plated carbon steel material which provides strength and offers good corrosion resistance in many environments. EASY TO USE TO USE: They are versatile threaded insert nuts that you can easily drive with them, easy to use. FEATURES: Insert nuts are advantageous over barrel nuts and T-nuts because they can be installed on one side of the room. 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. Number of pieces delivered: 20 Size: M8*15 lucky meet Note: The data is manual measurement, please allow 1-71cm error, due to differences between light and screen, there will be a certain color difference, the specific received in kind prevail.