I bought one of these... the fan was so noisy and annoying, I tore it apart and threw that fan away. I replaced it with two Arctic F12 Pro muffin fans (sealed bearings so they can operate in any orientation). The Camco solar panel puts out about 5 volts, so it won't spin the fans at full speed, but the fans are nearly silent, and can't be heard inside the trailer. I would not recommend the Camco unit, by the time I got done, I have more than $100 in the set up. The new vent cover was nicer than the one I had on my TT, so at least it looks nicer and actually protects the vent inlet from rain better than the old vent cover.
Steve