The Chim-A-Lator damper is operated by a convenient lever installed on the side wall of the fireplace. The lever has six positions to help control the amount of air draft. That means more heat when the fireplace is in use. The Chim-A-Lator mounts directly to the flue tile and therefore requires that the flue tile extends at least 1.25in above the crown. The Chim-A-Lator is 11in from base to lid and comes equipped with a 30ft cable. A 50ft replacement cable is also available and sold separately. It comes with a 7ft cable shield to protect the cable at rub points in the chimney. Measures 8in x 13in.