With the 3M indoor window insulator kit, you can lower your heating bills during the winter and make your home more energy-efficient. Part of 3M's line of energy-saving products, this kit includes window insulation film and a roll of double-sided mounting tape to create an airtight seal. Stretching the film removes wrinkles for a transparent view. This version of the 3M indoor window insulator kit enables you to insulate five 3-foot-by-5-foot windows. Included with this kit is a 1/2-inch-by-27-7/10-yard roll of 3M window film mounting tape to keep your insulation in place all season long.