- '' x 25 ' Length - R6 Insulation value. Required least in many an building codes across the country - Polyethylene jackets a long-lived, scuff - impervious vapor barrier that provides reinforced protection against prejudicial extremist - violet friable. - Installation is easygoing with the reinforcing fiberglass yarn scrim, which acts as a rip - stop and prevents tearing - Rigorously tested by Underwriters Laboratories, Inc. in accordance with UL 181, The basic for safety in Factory - Made Air Ducts and Air Connectors.