A basic cat flap is a hole inside your door that enables your cat to go and come according to their own preferences. This design isn't very secure and could provide easy access for burglars. Think about upgrading to a model that is lockable or automated with more security features. https://cat-flap-in-upvc-door-pan10985.blogproducer.com/37385204/using-a-cat-flap-in-bifold-doors