During the cold weather months, windows become a prime spot for energy loss. Duck® Max Strength® Brand Rolled Window Insulation Kits feature a puncture-resistant rolled film that is two times thicker than standard window kits to create an added barrier between the outdoor air and your home's inside. These heavy-duty window insulation kits help to block drafts that lead to high heating costs and are great for high-traffic or pet-friendly households. Our window kit film comes in an easy-to-use roll of shrink film, which means no measuring needed — simply cut the extra film off once applied. Plus, they are made with crystal clear shrink film for good visibility and are easy to install and remove. For best results, use on clean and dry surfaces, such as painted or finished wood, aluminum or vinyl.