Excellent Quality: These nuts are made of high quality zinc plated carbon steel which provides strength and good corrosion resistance in many environments. Easy to Use: These versatile threaded nuts will give you make them easy to use, easy to use. Features: Insert nuts are advantageous over cylindrical nuts and T-nuts because they can be installed from one side of the part.< /p> Note: the pre-drilled hole should be as deep as the length of the insert nut plus any part of the bolt that can be screwed past the end of the nut into the workpiece