New Insulation+Two Flaps: Petcoming dog door adds an insulation flap among Two falps to Insulates against cold air outdoor and improves warmth performance. In the meantime, the magnetic strips equipped on the double flaps and the dust strips on the frame can enhance sealing and effectively prevent the dust, and insects. PETCOMING All Aluminum Dog Door: This dog door is made of selected high-quality aluminum alloy, which significantly improves its sturdiness. Compared with other metal dog doors, it's more durable and has stronger structural stability, excellent resistance to deformation, rust and corrosion, and the paint does not flake off. Dog Door Size Details: Equipped with a spacious 18.7 x 9.92 inches flap opening, this dog door is suitable for large dogs weighing up to 110 pounds. Its design includes adjustable channels that can perfectly fit door or wall with a thickness between 1.26 and 2.08 inches.