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A through wall cat flap is a great method to allow your pets to move around whenever they like. Be sure not to put it too high into the wall. This can lead to energy loss and also the possibility of burglars entering your home. A gap in a cavity can also be a problem for future owners should you decide to sell your house. Cat doors made of glass are a safer alternative. Easy to install A cat flap that is built into the wall allows your cat to come and go when it wants. There are a variety of models available