3.9 mil foil tape is moderately thick. Strong adhesive, but residue-free after removal. Suitable for seal or repair all kinds of ducts, smoke pipes, exhaust pipes and vents. Aluminum foil tape also serves as a good barrier against dust, moisture, smoke, odor, and many chemicals. Thicker hvac tape for ducts, easier peel off backing paper and not easy crinkled and curled on itself. Used in electronic products, wrapping electronic products for shielding radiation to prevent interference. Foil tapes are also used for shielding EMI and RFI, eliminating interference, repairing reflective insulation, repairing sheet metal, and many other industrial and automotive applications. Industrial grade material, high quality, high tensile strength aluminum foil, epoxy coated, strong cold solvent resistant acrylic adhesive set on easy peel silicone paper backing to protect the adhesive and provide ease of use. Silver finish tape is processed from pure aluminum and adhesive, thicker foil and sticky adhesive support more strength. Extremely high tensile strength and stability. 3.9 mil thick professional foil tape is more durable, provides better insulation, and has a stronger adhesive. Flame retardant, moisture-proof, temperature-resistant, anti-interference, thermal conductivity, anti-corrosion, heat reflection. Perfect for indoor and outdoor use. Aluminum foil tape has super adhesion, insulation, sealing and tear resistant design. Heavy duty tape is easy to tear by hand without the need for additional tools. The aluminum foil backing will create an airtight and watertight seal to prevent water leaks. This high quality self-adhesive foil duct tape is ideal for joining and sealing insulation, duct wrapping, repairs and pipework. Suitable for repairing, sealing hot and cold air ducts, duct insulation systems, sealing aluminium, stainless steel and plastic seams/joints, temporary restoration of metal surfaces, copper pipe fixing, etc. Duct tape can be easily applied to most surfaces suc