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 nuts Versatile threaded nuts allow you to use them easily, easy to use. Features: Insert nuts are advantageous over cylindrical nuts and T-nuts because they can be installed on one side of the piece. 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 in the workpiece