Even small cracks and gaps around windows and doors can cause drafts that lead to high energy costs. Duck Brand Max Strength™ Silicone Weatherstrip Seals are used to seal smaller gaps up to 1/4 in. around windows and doors that may let outdoor air inside. They can also help keep out unwanted dust insects and pollen during the warmer months. Designed with silicone these self-adhesive seals come with a lifetime guarantee and won t crack or split over time. Simply separate the dual strip into two pieces cut to size and then apply to your window or door for added weather protection.