This mount is excellent for attaching to very thin substrates such as hollow doors and luan (wall material for most campers and RVs). drill . To install, make sure the small tabs on the underside of the flange are dug into the ground before tightening the screw. This keeps the fastener from rotating and flattening the tabs, and the metal is very soft and easy to remove. Threaded so tread lightly when using a drill to tighten. When installed correctly, these fasteners are a great way to attach things to thin, fragile substrates.