I've looked at Showhauler, NRC, and Trendsetter conversions with super slides and have found something a little unsettling. The exterior layer of the underside appears to be a heavy-duty corrigated cardboard. Of the Class A's that I've looked at, those coverings were made of aluminum or a heavy weight plastic substance and were attached substantually to the vertical walls of the slide-outs. It makes me wonder that if cardboard is being used for this covering what is going on with the rest of the slide-out. Can anyone fill me in as to this finding. Also, who makes the slide-outs for these conversion companies? Do they have a web site? Thanks in advance.