Aluminum Frames; High-quality Pvc Plastic Flaps With Built-in Uv Inhibitors GIVE YOUR PETS FREEDOM: No more planning your schedule around potty breaks, your four-legged friends can come and go on their time SOLID ALUMINUM FRAME: Designed to withstand wear and tear, the strong metal frame with its reinforced aluminum corners can handle active and multi-pet households DURABLE CONSTRUCTION: Includes a flexible, tinted flap; great for indoor and outdoor storm, wood, PVC, and metal doors CONTROL YOUR PETS? ACCESS: Use the slide-in closing panel to control your pet?s access to the outdoors and keep stray animals out of your home EASY DO-IT-YOURSELF INSTALLATION: Cutting template, detailed instructions and installation hardware included; fits interior and exterior doors between 3/8 in and 2 in thick DESIGNED FOR EXTRA LARGE PETS: Flap opening is 13 in W x 23 in H and is designed for pets up to 220 pounds QUALITY PROMISE: PetSafe brand has been a trusted global leader in pet behavior, containment and lifestyle innovations since 1998 to help keep your pet healthy, safe and happy