I made this block to cover the hole in the frame of our 8280WS where the slide ram comes through the frame. My concern was that mice or other small animals could get in between the under belly cover and the floor of our 5th wheel.
This shows the cover Front side
I used 1/2 inch plywood, drilled a 2 inch hole, cut in half, 2 metal straps and bungee cord to hold it together.
The back has 4 magnets to hold it to the frame and some foam weather strip to fill between the magnets.