Karavan Trailer Tube Plug

I made these to put in the open ends of the tubes on my dad's Karavan trailer (purchased at Home Depot). He has a 5'x8' foot model and the tailgate and sides all fold down. The caps that were originally on it wore out and the tailgate and sides rattled terribly when towing. These caps fit snugly and have ended the rattling. These caps take up the slack between the sides and the tailgate when latched. These fit snugly and can be tapped into place with a rubber mallet.