this is a special body coating. it's damn near a thin epoxy IMO. seems to work great but be very careful applying it. the fumes are very toxic.
When I rebuilt the underside of the celi, every part that I could sandblast got redone in POR15. After 5 years of storage and two years of driving beforethat not a single side of rust. The stuff is a PITA to put on, requires special prep work. Not only is the fumes bad, if you get it on any thing like concrete, its there forever. If you get it on yourself, you have to wear it off. Takes a few weeks... Damn good stuff. If you are doing a ground up rebuild and want your celi to last this is the stuff.
Good stuff, use it often... DEFINITELY wear garbage clothes and some kind of gloves !!! NEVER comes off clothes and takes days to get off your skin....lol (Trust me...)