| SR Insulated Ducting 4" X 25" SR INSULATED DUCTING ThermoFlo Technologies 'SRB' series is an industrial quality insualted duct manufactured "tough" for consumers' and installers' peace of mind. It consists of a three ply polyester laminate, fiberglass reinforced scrim, galvanized spring steel wire, wrapped with fiberglass insulation, which provides an outstanding combination of strength and tear resistance. A heavy duty fire retardant black polyethylene vapor barrier adds extra durability. The insulation reduces heat loss & condensation.  | Manufacturer's Product Information |  | | | |
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