J'B Aviation's compact insulated Flat Duct is an extremely flexible heating and air-conditioning duct. It is constructed without wire reinforcement, allowing it to be flattened and rolled up when not in use. The construction consists of two-ply, flexible, heavy-duty, highly abrasion-resistant, vinyl coated fabric with moisture-proof insulation between plies. A sewn-on abrasion-resistant scuff strip is also included. Cuff zippers and Velcro strips permit attachment of additional sections to form longer duct assemblies. These ducts are available with inside diameters of 8, 10, 12, and 14 inches, and are tolerant to temperature variations of -40°F to +275°F. The insulation has a minimum R-value of 8.0 or greater to provide superior temperature control.