The Aluminum Wall Shutter is a rear flanged exhaust shutter for areas where corrosion may be a problem. The frame and blades are mill finish aluminum. The blades have a galvanized reinforcement strip across the top of each blade for added strength and counter balancing efficiency. The blades have a felt seal on the leading edge for quiet closing and better protection from the weather. Ideal for use with direct-drive or belt-driven exhaust fans. Recommended for vertical mount exhaust applications only.