Width: 20mm / 0.79inch; Length: 50m / 164ft; Material: durable aluminum foil and silicone.One-side self-adhesive design.Heat resistance: Instantaneous:about 300C / 572F ; Short time:about 125C / 257F ; Long time:about 100C / 212F.Increases temperature efficiency, making this dryer foil tape great for insulation, heat sinks, AC-units, heaters and vents. Chemically resistant, thermally conductive (helping cooling/heating efficiency), heat and light reflective.This Metallic Furnace Duct Tape for HVAC is great for sealing hot and chilly air ducts, repairing metal seams and insulating aluminum duct pipes.