https://opensourcebridge.scien....ce/wiki/How_Much_Doe
http://brewwiki.win/wiki/Post:....Fitting_a_Cat_Flap_i
Cat and dog flaps in double glazing make it easy for your pets to go and come as they please. They are also great for keeping an eye on your pet whilst you are away from your home. It is possible to fit the cat flap onto an existing uPVC panel or double glazing glass sealed unit, but you'll need a replacement piece with a hole that is pre-made. A glazier can accomplish this with the right equipment and training. Easy to install Installing a cat flap