This premium window insulation kit from Frost King® is heavy duty and can be used in indoor and outdoor applications. For situations where toughness and extra strength are important, this insulation kit will stand up to the challenge. It's twice as strong as Frost King® brand's standard insulation kit and the double-sided tape is extra wide. Insulation film on windows helps increase their R-values by up to 90 percent, thus providing energy-saving efficiency. Insulation window kits also stop drafts and help lower your utility bills.