The trailers are equipped with (3) S/S 5-Gallon bottom drain VRP® provers each individually plumbed to (3) 110 -gallon transfer tanks. Service professionals are able to test 3 grades of gasoline for a total of 66 tests with the 5-gallon provers prior to returning to the fuel stations storage tank for dumping. Side vent provides additional protection from vapors. The trailer is available with optional on board pump-off system and hose reel.