Comfort Flame"s 6 inch pipe is designed for Comfort Flame and FMI direct-vent fireplaces. Features a galvanized outer wall and stainless steel inner wall. All Direct Vent and Wood Burning products require venting to the outside of the home to achieve proper ventilation and firebox combustion. FMI Products offers a full assortment of venting components to properly vent the Direct Vent or Wood Burning fireplace.