https://writeablog.net/bottlet....iger56/cat-flap-inst
https://jsfiddle.net/steelshade96/oe1x9g2d/
It is best to employ an professional to install a cat-flap in your home. DIY projects often result in poorly-fitted pet flaps that could allow in draughts or raise energy bills. SheffLOCK is able to install cat flaps on all kinds of doors, such as wood, uPVC composite, glass and even exterior walls. On average, it takes about 2 hours to install the cat flap. Cost of the pet flap A pet flap is an ideal way to let your cat come and go whenever it wants. If the flap isn'