I bought it at a local RV place. The sales guy said the were at a trade show where RVcare had a promotion on these covers, no doubt trying to take some market share from MaxAir. I also noticed the mounting was identical to MaxAir. Kind of nasty to copy MaxAir but it appears the MaxAir price is unnecessarily high in Canada - at least three times the cost of the one I got.
Yes, just four nuts to take off and the cover lifts off. I tested the lid opening before installing. It opens to about 45 degrees. There was a screen in the back of the cover, which I removed since there is one on the vent.