• Best energy-efficient pet door for extreme cold or hot weather
  
• Fits interior and exterior doors 1-5/8" -  2-3/8" thick
• Weatherproof double flap design ideal for strong winds and harsh climates
• Flexible flap withstands temperatures from -40°F to 110°F
• Strong, sturdy locking cover included for blocking access when needed; can be used on interior or exterior
• Heavy-duty ABS plastic locking cover for added security  

• High quality pet door: Double flap door mount pet door providing energy efficiency and weather resistance
  
• Versatile installation: Compatible with solid core doors, hollow core doors, metal doors, and storm doors 1-5/8" - 2-3/8" thick
• Superior insulation: 7/8" thick flap with a complete magnetic seal to resist winds up to 50mph
• Wide range of sizes: Four sizes available, from small for cats to extra large for large dogs, accommodating most breeds
• Lifetime Warranty: Backed by a Lifetime Warranty and Easy 90-Day Returns for peace of mind
• Made in the USA: High-quality construction ensuring durability and long-lasting performance
• Sleek design: Architectural extruded aluminum frame in white, black, or tan to suit your home's aesthetic
• Secure locking cover: Strength of 16 gauge steel to block access when needed
• Flexible flap design: Swings on a rod at the top to avoid cracking and flexing
• Customizable magnet strength: Option to add or decrease magnet strength for pet training or increased wind resistance
• Praised by many: Regarded as a high-quality, well-designed pet door, worth the investment for its durability and performance
• Withstands active pets: Flap remains functional and easy to clean, even with pets running through at full speed

There has been lots of discussion as to why the Endura Flap is such a , but for engineers or those looking for some more technical information here is a 74-page showing what makes it so special. For those living in a moderate climate, check out the .