The correct roof vent is going to be determined by the opening/vent on the topside of your Featherlite, opposed to the inside opening. You will need to get up there and measure to make sure you get the correct replacement.
The MaxxAir FanMate RV and Trailer Roof Vent Cover # MA00-955003 will fit over most standard 14"x14" vents. The Overall dimensions are 25" long x 18-1/8" wide x 10-1/4" tall.
The Fan-Tastic Vent Ultra Breeze Trailer Roof Vent Cover # DMC38FR will fit openings of 14-1/4"... view full answer...