[JRTJH]

All but the most expensive trailers now use TPO roofing. Keystone seems to get a "better wholesale price from Alpha Systems so I'd bet the kitchen sink that your roof is a Alpha Systems TPO membrane.

You can pull the plastic trim ring from the bathroom vent (4 screws). You'll find the membrane stapled to the frame where the factory cut it diagonally to make the opening for the vent to be installed. Pull those staples from one flap and inspect it. If it's the same color front and back, it's TPO. If it's black with a colored top surface, it's EPDM. There was a third type, a "felt covered TPO" that was used in 2012-2014 models, but that type of roofing has not been used in recent years.

So, once you verify that your roof membrane is TPO, be sure to use the appropriate "self leveling sealant" on the flat surfaces and "Non-leveling sealant" on the vertical surfaces. Most people use about a tube per inspection. If you store opened tubes in the refrigerator with the tip properly sealed, it will keep for several weeks. Don't plan on buying in bulk, the sealant does "expire" and storage can be an issue in most parts of the country. It's better to keep it at an even temperature in a low humidity environment. I believe that it's better to let the dealership throw away the bad sealant rather then for me to do it. It's much cheaper that way too.