TRBN BS 12" WTHRWD Wind Turbines are a type of attic exhaust vent that make up half of a balanced attic ventilation system for each roof. Intake vents make up the other half of the system. Together they help remove any built-up heat and moisture inside the attic for year-round ventilation. A non-electric alternative to ventilation, turbine vents use the natural force of wind and air pressure to spin and vent out stale attic air. They do it with a series of specially shaped vanes that catch the wind and provide rotary motion. This pulls hot, humid air from the attic. Turbine vents provide a low-cost ventilation alternative in areas where wind speeds of at least 5 mph are typical.; ; Brand Name: Air Vent Sub Brand: Air Hawk Height: 18.9 in. Diameter: 12 in. Color: Weatherwood Material: Aluminum Product Type: Turbine and Base Paintable or Stainable: No Shape: Circle Screen Included: No Wildlife Guard: No Net Free Area: 95 sq in Vent Type: Wind Turbines Pitch: 3/12 to 12/12 UV Resistant: Yes Features 1 EACH USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.