The Extreme Weather Pet Door protects your home from extreme temperatures while giving your pet the freedom to come and go. This durable door with a 3-flap system delivers maximum energy efficiency that's 3 1/2 times higher than PetSafe standard single-flap pet doors and offers protection from the elements. A snap-on closing panel provides additional insulation. Frame dimensions are 12 1/2" x 19 7/8" and flap opening is 10 1/8" x 16 1/4". Suitable for pets up to 100 lbs.