Lomanco® 905W Series 900 Vari Pitch Adjustable Louver Vent, WhiteThe Lomanco Series 900 Adjustable Louver fit roof pitches of 2 1 2 12 to 9 12. The ingenious design actually forces the louver blades to pivot, changing angle as the unit is adjusted. This permits maximum air flow capacity while assuring optimum protection from the weather. Constructed entirely of heavy gauge aluminum Adjusts from 2. 5 12 to 9 12 roof pitch 8" x 8" perma coated screen 1 1 2" wide mounting flange Pivoting blades provide maximum weather