Polyken 229 MULTI-PURPOSE DUCT TAPE - VERSATILE PERFORMANCE Heavy duty Contractor Grade. Excellent on flex duct, seal duct work, general purpose packaging, hold down fiberglass insulation, condensation barrier in refrigeration. Applications Sealing heating and air conditioning duct connections. General purpose packaging and bundling. Hold insulation materials in place. Features & Benefits Specially formulated pressure sensitive adhesive. Excellent tensile strength, adhesion and tack properties. Designed for the most demanding HVAC applications. Extra thick adhesive to provide excellent sealing bond to all types of surfaces.