This Top Damper - masonry chimney damper is made of stainless steel and cast aluminum for an unmatched durability. The Top Damper is designed to help reduce heating and cooling bills; to prevent downdrafts and odors; to keep out rain, snow, birds, and pests; and to help reduce outside noise. A simple and ingenious system allows opening and closing the shutter with the help of a vertically acting spring damper which operates easily from inside your fireplace. When closed, the Top Damper serves as a chimney cap and, with a slight pull of the chain, it releases the spring open when you are ready to enjoy a nice fire. The parts required for the installation and 30 feet of stainless steel cable are included. Suitable for any masonry chimney with an inside flue from 6" x 6" to 9" x 9". Does not require the addition of a safety device; often required and constraining.