This is a threaded pass through so that it can be securely closed off. I am using this in my garage ceiling for a lifting point I have installed. This will require a 6" hole in whatever material this will be installed in. Also, the back-up ring was designed to avoid using anchors if you have access to the back side of the material. The mounting holes where sized for standard Kreg pocket hole screws. There are also small holes in the pass through which where designed to secure a piece of rubber as a seal but really isn't needed.