Dayton Louver Damper,Adjustable,12H x 12W 20UA20

15 in.h 15 in.w drnbl extrd alu intake louver, louver type stationary blade, frame type flanged, frame depth 4 in, mounting style surface mount, outside height 11 1/2 in, outside width 11 1/2 in, rough opening height 12 in, rough opening width 12 in, louver maximum intake 310 cfm, maximum exhaust 443 cfm, maximum outside width 14 1/2 in, minimum outside width 14 1/2 in, flange width 1 1/2 in, free area 0.4 sq ft, beginning point of water penetration 1,031 fpm, maximum air velocity 3500 fpm