We are going to have to change our cat flap as we have been invaded a couple of times recently by a new cat to the area. Water pistol doesn't seem to have put the new cat off coming in at all times of the day to sleep, eat and spray.
On line reviews for both the magnetic and infra red cat flaps seem to suggest that they can be noisy and expensive for replacement collars and that the flaps can be forced open relatively easily.
Has anyone experience of the cat flaps that work by scanning idntichips? If they work without too many cons then I am happy to pay the price.