High Quality: These insert nuts are made of galvanized carbon steel, which gives them great strength and good corrosion resistance in many environments. . Easy to Use: These are multi-purpose thread insert nuts that you can easily mount with them, easy to use. . Features: Insert nuts are advantageous over cylindrical nuts and T-slots because they can be installed from one side of the part. . Matching Kit: There are 6 different size insert nuts (please see the detailed size in description or pictures), so you can handle your project for free. . Note: The pre-drilled hole should be as deep as the length of the nut to be inserted plus a portion of the bolt that can be screwed onto the end of the nut in the room. Translated with www.DeepL.com/Translator (free version)