ENERGY-EFFICIENT & WEATHERPROOF: Endura Flap pet door for walls features a double flap design for superior insulation in all climates, reducing energy costs and maintaining a comfortable indoor environment year-round; flap seals tightly with magnets and blocks winds up to 50mph; large flap measures 10" x 19" and is suitable for pets up to 28" tall DURABLE AND LONG-LASTING: Built with a heavy-duty aluminum frame and flexible polyolefin polymer flap, this wall dog door resists extreme temperatures as low as -40°F and holds up in harsh weather, providing reliable access for pets year after year EASY TRAINING FOR YOUR DOG OR CAT: Three-sided magnetic seal is adjustable to ease training and help timid pets acclimate, while still providing a secure, wind-resistant seal once your pet is fully comfortable using the door STEP-BY-STEP INSTALLATION: Includes clear installation instructions and tips for standard and special wall types; telescoping tunnel fits walls 2" to 7.75" thick with no need for framing kits—see “Endura Flap for Deep Walls” for walls over 8" BE CONFIDENT IN YOUR PURCHASE: Made in the USA from premium materials; includes a secure locking cover and recyclable, non-toxic flap; backed by a lifetime warranty and supported by replacement parts to ensure lasting performance The Endura Flap Mount Pet Door in black, extra-large size, is the ultimate solution for pet owners seeking energy efficiency and durability in extreme weather conditions. Designed to fit walls with a thickness of 4.5" to 8", this pet door features a single or double flap system that provides superior insulation, keeping your home comfortable and lowering energy bills. The durable flaps are capable of withstanding temperatures from -40 to 110 degrees Fahrenheit, and heavy-duty magnets line the flaps to resist winds up to 50 mph. The high-quality aluminum frame ensures long-lasting durability and protection against harsh weather. For added security, a strong and sturdy locking cover is included, which can be used on either the interior or exterior of the pet door. This door is specifically engineered to accommodate both large and small pets, with a taller and narrower flap design. Installation is straightforward but requires advanced skills, making it suitable for those who are handy with tools. The pet door includes everything you need for installation, along with an aluminum telescoping tunnel for easy installation. The Endura Flap Wall Mount Pet Door is highly praised for its performance and reliability, making it a worthwhile investment for pet owners looking for the best in insulation and security. With its robust construction and superior engineering, this pet door ensures long-lasting satisfaction and peace of mind for you and your pets. Note that this product is not recommended for use by kittens or very small dogs.