A Rainbay as part of a PDI listing would be a facility that has overhead sprinkler/spray nozzles to test the integrity of the exterior seals and windows and roof. We have one we built to test for water leaks after we repair a RV. Also, to verify that there IS a leak after a customer complains when he brings his unit in. We usually do the test then have the customer come out to verify that there are no leaks or the leaks we found and fixed are now gone. Saves a LOT of time and hassle for the customer. Doug