HEAVY DUTY ENERGY EFFICIENCY: Endura Flap thermo panel features an energy-efficient design with LoE glass, magnetic sealing dual-layer flap, and heavy-duty aluminum frame, providing excellent insulation and durability for pet owners extra large flap measures 12" x 23" and is suitable for pets up to 34" tall,DESIGNED FOR SLIDING GLASS DOORS: the pet door secures into the track of your existing sliding glass door, requiring a track width of at least 1" extra-large pet door will require up to width in your slider, allowing you to continue using your sliding glass door normally,VERSATILE INSTALLATION: available in 3 different height ranges, with a sliding installation mechanism to accommodate various door models, the thermo panel is quick and easy to install, ideal for renters and vacation homes without requiring the need for permanent installation,DURABLE AND SECURE: the Endura Flap thermo panel includes a heavy-duty molded ABS locking cover and C-Clamp Lock, ensuring safety and control when needed, while allowing your pets the freedom to enter and exit as they please for additional security, pet owners can consider using a charley-bar to fix the sliding door in place,LIFETIME : Endura Flap pet doors are proudly built in the USA, using high quality materials, and backed by a lifetime experience worry-free satisfaction for you and your pet