Master Flow SGM20 Power Vent Automatic Shutter, 16-1/2 in L x 16-1/2 in W Rough Opening, Aluminum, White

Use with all attic power gable mount vents, moving air opens the louvers only when the power vent is operating, when vent is off, shutter helps prevent infiltration of rain, snow, insects, etc, maintenance-free white aluminum construction, can be painted if desired.