US Stove's D6 model is a durable cast iron damper. Features a spring loaded removable steel shaft, closed by formed spring wire button on shaft end. Fits all standard single wall pipes. US Stove has been bringing warmth to homes across the nation for 140-year. US Stove has a wide range of Automatic Circulators, Plate Steel Heaters, Cast Iron Heaters, Pellet/Multi-Fuel Heaters and Gas Fireplaces from which to choose. The large selection of stoves and accessories will ensure warmth of your home with safe, quality products.