Mushroom attic vents for the front and rear: check this link,
https://www.montanaowners.com/forums...ad.php?t=76056
The black ones are tank vents. I guess they are intended to keep debris out of the vents but still allow the pipe to breath. When I lost the top off one of mine I replaced it with a larger size abs cap. Ran a screw through the sidewall of the cap directly in to the pipe. Think I put a 2"cap on an 1.5" pipe. Been there for years. with out an issue.