Ventamatic Cool Attic 12" Aluminum Mill Wind Turbine Attic Vent

12" premium externally braced wind turbine attic exhaust vent. Aluminum construction. Premium grade upper and lower stainless steel ball bearings with integrated molded shield to protect bearing raceway. Adjusts to 12/12 pitch. Premium bracing system engineered for high wind resistance. Tested to ensure durability and performance in extreme temperatures and high winds. This exhaust vent requires adequate soffit intake vents. Requires 432 sq. in. NFA (Net Free Area). Includes: Base and riser. Lifetime limited warranty.