Nashua 557 Premium Grade Flex Duct Tape is high performance duct tape specially engineered for flex duct systems (PRINTED). The tape acts as a superior closure system for use with flexible air ducts and air connectors. Recommended for use on UL list flexible air ducts in accordance with manufacturers' installation instructions. For use in heating, air conditioning, ventilating and refrigeration applications. Suitable for bonding, protecting, holding, repairing, and patching. Nashua 557 is a UL 181B-FX listed product. It possesses excellent shear properties and superior quality, performance, and tensile strength. Shows excellent resistance to mold growth, humidity, flame spread, smoke generation, and the effects of high temperatures. Low VOC content and can contribute toward requirements for EA Credit 1 (Optimize Energy Performance) and toward satisfying EQ Credit 4.1 (Low Emitting Materials) under LEED®.