Cat flaps are great inventions, they mean you don't have to keep getting up to let your kitty in or out and if they are anything like mine then you'll do that a lot.
The only down side to them is that the they also let your neighbours kitties into your home and if you have a basic model there's nothing to do to stop this. It's not a nice experience for your feline, they tend to feel threatened. Plus have you ever seen them react to another feline intruder, back arched tail, puffed out, they are not impressed. Why should they be, some random kitty has decided to pay their home a visit without an invite.
Over the years as technology has improved so has the humble cat flap. Previously you were able to buy a magnetic model, which only opened if your feline friend was wearing a magnet on their collar. The development of the animal chipping system paved the way for a more sophisticated cat flap - Microchipped ones. These only let an animal in if they recognise the chip implanted by the vet. It's the same technology that carries the information that is useful if your feline friend becomes lost or stolen.
So if you're having problems with extra visitors of the feline variety and you've already had your cat micro chipped then this type of flap could be an extremely good at solving your problem.
One of the most popular models which uses this technology is the Sureflap. Not only have I heard people rave about this product but their customer service seems outstanding too. There's also the Portepet which is ideal if you have a Maine Coon breed or small dogs who will also use it.
If you haven't got your cat mircochipped already you might want to consider doing so. It allows your kitty's details to be stored on a database so if they're lost or stolen, any vet can find your details so you can be reunited. It's also the only way for your information to be carried if your furry friend doesn't like wearing a collar.
If you are thinking about installing a cat flap you may need to get a special glazed panel manufactured if you already have double glazing. They are very easy to install into a wooden door. The hole can be cut out with a hack saw and the flap slotted and fixed into place with screws.