"AIR VENT" EXTERNAL BRACE TURBINE 12" Uses natural force of wind to vent the attic from the soffit to the turbine Turbine has a dual Delrin ball bearing system Rust free aluminum construction Moves 345 CFM at 5 mph wind Includes base Dade county approved up to 110 mph wind speeds Dade county approval code No. 98-0209.01 Mill finish Limited lifetime warranty Boxed