Duct tape, also called duck tape, is cloth- or scrim-backed pressure-sensitive tape, often coated with polyethylene. There are a variety of constructions using different backings and adhesives, and the term 'duct tape' is often used to refer to all sorts of different cloth tapes of differing purposes. Duct tape is often confused with gaffer tape (which is designed to be non-reflective and cleanly removed, unlike duct tape). Another variation is heat-resistant foil (not cloth) duct tape useful for sealing heating and cooling ducts, produced because standard duct tape fails quickly when used on heating ducts. Duct tape is generally silvery gray, but also available in other colors and even printed designs.