Exactly...the unit the OP is looking at comes with 3 screws and is designed to be mounted that way, not glued. YES, for the millionth time we get that you are not putting this on an RV.
My point was that this unit can be mounted to any 1.5" PVE, PVC or ABS pipe using the included screws. You DON'T want a glue install, any type of vent cap is meant to be removable so you can use the vent as a cleanout point for snake access if necessary.
The joint doesn't need to be airtight since air is escaping there anyway, hence why they call it a "vent"...
