12" internally braced wind turbine attic exhaust fan. Aluminum construction. Derlin bearing system for quiet, long-lasting, and smooth operation. These vents use the natural force of wind and air pressure to spin and vent out stale attic air. Large flashing for easy installation. This exhaust vent requires adequate soffit venting to meet minimum ventilation code requirements. Provides 95 sq. in. of net free area. Miami-Dade County approved. Includes: Base and riser. Mill finish. Lifetime limited warranty.