See this thread for
http://www.sunlineclub.com/forums/f6...hlight=maxxair for general info about Maxxair products as well as the installation. This thread includes several other links including a post by JohnB on how to replace the OEM vent. If you plan to replace the entire vent the MaxxFan I installed is a viable alternative, but pricey if you don't want the fan function.
The MaxxFan has a positive lock for the closed and open position and it will not move if it is locked. I've never experienced one of the other vents opening on its own and I've towed 4 different trailers over thousands of miles.
We also have
MaxxAir II covers on the other vents. These are a really good deal at CW now as they come with the EZ open brackets that just need a clip removal to flip them over and clean up around the vent lid.
Henry