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If you have a cat or dog installing a pet flap in your French or patio doors is a good idea. It allows them to get in and out without you needing to open the door. There are many cat flaps available designed to fit in uPVC or composite doors as well as wooden doors. Some have a four-way locking system that can be set to exit only by entering only the open position, or both. Installation Cat flaps are an excellent method of letting your cat out