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This cat flap that is insulated comes with a double-flap mechanism and offers a good level of protection for different climates. It can be installed in wood, uPVC, glass, and metal doors. A tightly sealed door is essential, especially in colder weather. It stops warm air from being sucked out and cold air from getting in which can save money on energy costs. Wind Resistance By preventing cold air entering your home and keeping warm air in the cat flap, it keeps it warm.