[Bob86ZZ4]

Yep, seconds on that one. I've owned 2 rv's. My old one had three roof vents similar to that ebay one, except the one in the bathroom and the one in the shower both had fans. A must I'd say. My rig now has two "Fantastic" vents. They are the best and well worth the extra money. Motorized open/close, and rain sensors. So they close and turn off if it starts raining. And you can open them and not have the fan on if you want, and they'll still close if it starts to rain. I also put the big covers over mine so you can have them open when going down the road. Which effectively makes the rain sensors not needed since the covers allow you to run the vents in the rain. The Fantastic fans are designed pretty good to make them not that likely to leak if you caulk them right. And the big covers add another level of leak prevention. For sure plan on at least a couple vents. One of mine is right above the kitchen and they didn't put a exhaust hood above the stove and it works pretty good for cooking odors and heat exhaust.