Flexible Duct - Insulated



Type 4B High Pressure Flexible Duct Insulated 

Construction Features

The Flexmaster U.S.A.® Type 4B is manufactured to meet the highest quality standards in strength, permeability and fire resistance required in a flexible duct. Tested to UL standard 181, this Class 1 Air Connector is fabricated for application in a low to high pressure HVAC air distribution system.

Duct Fabric

A heavy, PVC coated, Fiberglass cloth fabric, mechanically locked to the duct helix without the use of adhesives.

Duct Helix

Made from corrosive resistant galvanized steel, the duct helix is mechanically formed to attach the duct fabric without the use of adhesives.

Vapor Barrier

Black, fire retardant, Polyethylene material. Excellentstrength at low temperatures. Will not age harden.


Fiberglass insulation jacket, factory wrapped.

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