It is best to hire an expert to install a cat-flap in your home. DIY projects usually result in poorly fitted pet flaps that can allow in draughts or raise the cost of energy. SheffLOCK can be fitted as a cat flap in most kinds of doors like wood composite, https://cat-flap-in-upvc-door-pan30206.blogozz.com/30187189/using-a-cat-flap-in-bifold-doors