I have a 33' long 5th wheel trailer that's 12' high.  After having extensively worked this unit over with 3M's fiberglass gelcoat restorer and wax, a task that took considerable effort over more than a week of chipping away at it, I was happy with the results.  That said, I live in the desert and figured a good coat of Mequire's Flagship Boat product would be beneficial if for nothing else as to add in some UV protection (this product touts that as a key attribute).  So a couple of weeks after the 3M work I applied this product to my large trailer and the results were extremely disappointing.