The Hercules Multi-Blade dampers for residential zoning systems have been engineered to include many features. The heavy neoprene blend on top and bottom ensures a tight rattle free seal and they are ribbed for strength and extruded from lightweight aluminum. The sleek frame profile provides maximum strength without excessive reduction of free area inside the ductwork. The extruded aluminum blades are mounted with friction minimizing nylon bushings to provide easy transition between opening and closing.