GREAT QUALITY: EASY TO USE: FEATURES: ASSORTED KIT: There are 6 different sizes of nuts (see detail size in description or photos) so you can manage your project for free. NOTE: Description: An insert nut provides a threaded socket for a piece of wood, similar to a wall anchor. Features: These insert nuts are made of high quantity zide plated carbon steel for durability and rust protection. The screw nuts have an external thread and a hexagon socket.They are screwed using a hexagonal key. Insert nuts are advantageous over barrel nuts and T-nuts because they can be installed on one side of the workpiece. There are different size screw nuts and different screw sizes that you can choose for your project. The pre-drilled hole should be as deep as the length of the insert nut and any part of the bolt that can be threaded beyond the end of the nut into the workpiece.