https://yogicentral.science/wiki/Cat_Flap_Fitters
It is recommended to hire an expert to install a cat-flap in your home. DIY projects usually result in poorly fitted pet flaps that could allow in draughts or raise energy costs. SheffLOCK can be installed as a cat flap in most kinds of doors like wood composite, uPVC, composite, glass doors, as well as external walls. On average, it takes around 2 hours to install the cat flap. The cost of the pet flap A pet flap lets your cat to move around whenever it pleases. However, if the flap is not correctly installed, it may allow heat escape