Can you recommend a vent cover that will be easy to attach to the vent rather than trying to attach it to the trailer skin? I have a 2018 surveyor 265 RLDS
I think you will find most, if not all vent covers do as No-Fish said, they attach to the metal frame of the vent, ... the three that I've installed sure did, ..... install video below, ...
Hands down Maxxair...easy install...if you get the Maxxair 11 which is only a few dollars more, it comes with cotter pins to flip the lid for easy cleaning without having to use tools.
Maxxair Fanmate covers come "Standard" on Rockwood & Flagstaff Units! If your unit has the Maxxair Roof Flange installed you Only have to acquire the "Maxxair Fanmate Cover and R-Pins" to install No Tools or Drilling Required! If another type roof flange is installed simply buy the Cover and L bracket Kit! If you install the Maxxair II the bracket kit will be needed! Youroo!!