This power blower has a 1.5 amp 12V DC fan that achieves 100 CFM, yet it fits in just a 6-1/4" diameter rough opening. The efficient centrifugal blower wheel ensures quiet ventilation. Airstream and other manufacturers used this style unit starting in the 1970s.

It requires a roof thickness of 1-1/2" to 4-1/2". The smoke lid extends only 3-1/4" above roof when in the open position.

White interior with garnish included.

Easy one-hand operation open/close.

The thick steel base is held to the top of the trailer with eight #8 sheet metal screws (not included).  They are on a 7" diameter circle evenly spaced.  Screws should be approximately 3/4" long, depending on your roof structure.

In order to access the holes during installation, you should temporarily remove the two Phillips screws holding the lid to the body of the fan.  Bed the steel base with 3/4" wide and 1/8" thick butyl putty tape very carefully set on the flange before inserting the unit into the roof opening. 

After installation, apply a perimeter bead of Trempro 635 polyurethane caulk around the base, but leave the drain hole unobstructed.

The interior garnish is attached with three #8 sheet sheet metal screws (not included).  Interior screws need to be at least 3/4" long.