This Seal Tight masonry chimney damper is made of durable cast aluminum. Its low profile offers the advantage of fitting under an existing chimney cap or being very discreet on top of the chimney. It is designed to help save in heating and cooling bills; to prevent downdrafts and odors; to keep out rain, snow, birds, and pests from entering the chimney, while limiting outside noise. A simple and ingenious system operates on a hinge point to allow opening and closing the shutter on a single pivot point which operates easily from inside your fireplace. The system uses two types of seals that are never exposed to the outdoor elements and which promote one of the tightest seal, superior to similar dampers. 30-ft. stainless steel cable and all mounting hardware is included. Suitable for masonry chimney with an inside flue from 6 1/2″ x 10 1/2″ to 9″ x 12 3/4″.