Polyken 338 FSK Insulation Jacketing Tape is a Foil, Scrim, Kraft laminate tape coated with a synthetic rubber adhesive suitable for used to seal and patch FSK duct boards and blankets. Provides extra strength seal to maintain vapor barrier integrity. Used for sealing insulation and repairing in cooler / refrigeration applications. Polkyen 333 is high strength & tear resistant; UV , moisture and mold resistant; and provides for a super high tack, aggressive bond to surfaces. Diamond pattern matches most FSK boards and blankets.