During the cold weather months, windows become a prime spot for energy loss. Indoor Duck® Brand Max Strength™ Roll-On® Window Insulation Kits feature a puncture resistant film that is stronger than standard window kits to create an added barrier between the outdoor air and your home's inside, helping to block drafts that lead to high heating costs. These heavy-duty Max Strength kits are great for high-traffic or pet-friendly households. Our window kit film comes in an easy-to-use roll with a pre-taped top edge, 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.