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; small flap measures 12" x 23" and is suitable for pets up to 36" 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