I used #10 ss bolts with smaller washers ( to fit the ss straps)...dosent have to be anything large as the force is down and not out. I was able to install the bolts&nuts below the medicine cabinet hidden by a rack full of wife stuff so not even unsightly. The outside plate is made out of 1/4in starboard. Can order small pieces of it, or similar brand, from TAP plastics. Can get the SS strap on line.I like this idea. I have one of these on my roof tent but have considered moving it to the trailer. I like this simple solution.