Dundas Jafine's Flexible Insulated Duct is UL 181 listed as a class 1 air duct and bears the UL mark. This duct consists of a flexible helix core made of 2 ply polyester laminate and corrosion resistant galvanized wire. It is surrounded by a blanket of formaldehyde free fiberglass insulation that helps to reduce heat and cool loss, as well as jacketed by a heavy duty, fire retardant, black polyethylene vapor barrier.
Dundas Jafine Bpc425r6 Insulated Flexible Duct with Black Jacket, 4inches by 25feet