PetSafe’s Extreme Weather Aluminum Pet Door has a three-flap system that is adjustable and flexible with magnetic seal to keep the weather outside. The center flap is fully insulated, and the metal frame has reinforced aluminum corners. The door easily fits into paneled, wood, PVC and metal doors 1 1/2 in.—2 in. thick and installation is a DIY project. Available in three sizes for pets up to 220 lbs.