As I can not put a cat flap, I opted for the infrared sensor doorbell. The balance is super positive. I do not have to leave a window open almost continuously, I do most monitors every five minutes if my cat is behind the window (especially in rainy or windy) and my cat has to worry being outside without knowing if and when he can go home to take shelter ... In short, this is happiness! Sensor easy to install and you can wander its case anywhere in the house. Among the available music, you have one of the Pink Panther ... Very funny!
