DuraPlus chimney is a triple-wall, all-fuel chimney system that is for use with wood stoves, fireplaces, furnaces, boilers, stoves, ranges, water heaters, or other appliances fueled by wood, oil, coal or gas. DuraPlus is designed to stay cool on the outside, to boost stove efficiency, and to provide for a fire-safe design that protects both the chimney and the building. DuraPlus chimney systems lock tightly with twist-lock precision and require a 2" clearance to combustible materials. Please Note: All Stove & Chimney Pipe is chosen and classified by the inside diameter. If your flue has a 6" Inside Diameter you will choose from the 6" Stove and Chimney Pipe categories.