This is a metal threaded insert that is 2"L x 1/2"D, with a 5/16" thread. It is used for installation in wood, and is made to go with a standard 5/16" bolt. It also allows for easy removal of the part! To give just one example of this hardware's use: by combining this with our install hardware service, you can not only get a bolt added to your bunfeet, you can also get the threaded insert to put it easily in your couch!