Air Vent 12-in Aluminum Internally Braced Roof Turbine Vent

As a non electric alternative to ventilation these vents use the natural force of wind and air pressure to spin and vent out stale attic air. Turbine head measures 19.25 inches x 19.25 inches - internal base opening is 12 inches Provides year-round ventilation Large flashing for easy installation Patented delrin bearings provide long-lasting quiet operation with no metal parts to squeak CA Residents: Prop 65 WARNING(S)