EXCEPTIONAL ENERGY EFFICIENCY: Endura Flap thermo panel is designed with dual-pane LoE glass and an insulated dual-layer flap, ensuring optimal insulation for your home and providing a comfortable environment for your pets even in extreme weather conditions; medium flap measures 8" x 15" and is suitable for pets up to 21" tall SEAMLESS INTEGRATION WITH SLIDING GLASS DOORS: this pet door is specifically designed for sliding glass doors, allowing for hassle-free installation without altering the door's functionality; adjustable height ensures a perfect fit for a wide range of sliding glass door models; medium pet door will require up to 12-1/4" width in your slider, allowing you to continue using your sliding glass door normally SECURITY & PEACE OF MIND: The Thermo Panel pet door features a heavy-duty molded ABS locking cover, strong as 1/16" steel, and a slide lock (consider a charley-bar for additional security); the robust aluminum frame guarantees long-lasting durability, allowing your pets to enjoy the freedom of coming and going as they please IDEAL SOLUTION FOR RENTERS AND VACATION HOMES: The spring-loaded top design allows for easy installation and removal, making it a perfect choice for those who rent or have vacation homes; permanent installation is not required, ensuring you can take the pet door with you if you move BUILT & BACKED FOR LIFE: Endura Flap pet doors are constructed with high-quality materials in the USA and backed by a lifetime warranty; enjoy worry-free satisfaction for you and your pet, knowing you have a top-of-the-line pet door solution The Endura Flap Thermo Panel 3e offers a practical and efficient pet door solution for sliding glass doors. This product features an easy-to-install design that seamlessly integrates into your sliding door's inside track, requiring no permanent alterations. This makes it especially suitable for rental properties or temporary residences. Crafted for durability and functionality, the Thermo Panel 3e boasts a heavy-gauge aluminum frame, ensuring strength and longevity. The inclusion of Low-E glass in the panel enhances energy efficiency by reducing infrared and ultraviolet light exposure, an essential feature for maintaining a comfortable home environment. This pet door offers adjustable heights and can be custom-sized to fit a variety of sliding glass door models, accommodating tracks that are at least 1" thick. This versatility is complemented by a choice of colors - white, black, and brushed aluminum - allowing you to match the pet door to your home's interior design seamlessly. The Endura Flap Thermo Panel 3e is designed with your pet's comfort and safety in mind. The polyolefin polymer flap is built to withstand extreme temperatures, as low as -40°F, and includes a magnetic closure on three sides for enhanced weather resistance. The adjustable step-over height enables you to tailor the pet door to your pet's size, ensuring their ease of use.For security, the product includes a heavy-duty molded ABS locking cover and a C-Clamp Lock, providing peace of mind when additional safety measures are needed. The Thermo Panel 3e is highly rated by pet lovers for its exceptional insulation, durable construction, and the freedom it offers pets to move in and out at will. To support your investment, the product comes with a lifetime warranty and US-based customer support. Pet door panel includes a center post draft stopper and foam weather stripping. Adjustment range fits slider heights between 77.25" - 80.25".