View cart “#2460: Exhaust Vent (closeable duplex)” has been added to your cart. #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 #3411: 75mm (3″) Warm Air Register $53.00 Add to cart #3413: 75mm Warm Air Wye $72.00 Add to cart #4416: 75mm/60mm reducer for 3413 $41.00