Goes along with the inner flange and inner locking band (with centering extension). The outer locking band is on the outside for more help, which makes it a more robust technique. Contaminants of combustion are certainly not trapped throughout the flue like it is commonly present in the corners of https://grease-tight-extract-duct22334.blogthisbiz.com/44092870/the-ultimate-guide-to-fire-resisting-ductwork-insulation