Seal Tight Damper is low profile and top mounted damper made of stainless steel and cast-aluminum. This gasket system provides effective air tight seal by using a liquid gasket which hardens to form a seal. The primary gasket sits in a channel inside the frame, while the secondary liquid gasket sits underneath the front side of the damper lid - the 2 seals create a very efficient seal. An open damper is like an open window, when closed this damper is a great money saving solution. Heat loss from a fireplace accounts for roughly 8% of your homes heating cost. This seal tight damper helps prevent that loss.