#4401: 3.5″ Warm Air Duct Insulation (per foot)$7.00 #4401: 3.5" Warm Air Duct Insulation (per foot) quantity Add to cart Description Description Fits over #3410 ducting for additional insulation. Sold in up to 6′ pieces. Related products Add to cart #602307: 28/45mm Exhaust Adapter $59.00 Add to cart #5316 Isolation kit $18.00 Add to cart #602293: Drain Loop $122.00