The Energy Chimney Top Damper is a low-profile top mounted damper that serves as a chimney cap! This damper will help prevent heat loss - keep you warm and saving you money. With precision engineering this damper is easy to open and close. It is the perfect upgrade for fireplace chimneys in older houses that never had a damper. See Video How to Install - https://www.youtube.com/watch?v=VGz8zejDIKA 12" x 12" Flue and larger Retails New Between $300-$400