12" superior 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. Includes: Base and riser. Lifetime limited warranty.