View cart “#5430: Cold Air Inlet Vent” 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 #5635: 2.5″ Warm Air Duct (per foot) $10.00 Add to cart #3417: Bulkhead fitting $40.00 Add to cart #5430: Cold Air Inlet Vent $12.00