Width: 55mm / 2.17inch; Length: 20m / 66ft; 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 ideal 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 ideal for sealing hot and chilly air ducts, repairing metal seams and insulating aluminum duct pipes.