When sealing ducts and other surfaces for heating, ventilation and air conditioning systems (HVAC), it's essential to have a strong, long-lasting foil tape that can stand up well to hot and cold temperatures. The 3M™ Foil Tape 3340 has the combination of 2.0 mil aluminum foil backing and strong, pressure sensitive acrylic adhesive that gives our tape a superb operational temperature range of -40°F (-40°C) to 300°F (149°C) making it ideal for sealing rigid fiberglass duct boards and flexible air duct systems. The foil backing also serves as an excellent barrier against moisture, dust and many chemicals — making it strong, durable and long-lasting. The very low moisture vapor transmission rate makes the tape a good sealant and the acrylic adhesive supplies superior temperature and UV resistance to give you a strong, lasting and reliable bond. It also has an easy releasing poly coated kraft paper liner to protect the adhesive and keep the tape ready for use. 3340 tape meets requirements for UL 181 A-P and UL 181 B-FX Listings as a measure of reliability and quality standards. 3M™ Foil Tape 3340 is used in a variety of applications including heating ventilation air conditioning (HVAC), duct closure, vapor seal on reinforced fiberglass duct board, rigid fiber glass duct board, and flexible air ducts and air connectors across a number of industries, including: transportation, specialty vehicle, metalworking, construction, automotive, military and government, general industrial, MRO, electronics and aerospace.