The GAF Master Flow Aluminum Slant Back Roof Louver is designed for attic ventilation. The fully enclosed hood deters rodent and insect infiltration and leaf and pine needle clogging. The aluminum slant back roof louver is an excellent choice against weather infiltration, especially in steep-slope applications.
Lighter gauge aluminum and cost slightly more than in store purchase. Hail would damage this easily. I used it to avoid a return hassle but would not put it on anything but a shed