This cat flap is fine except for the fact that the door shears off easily. This is a particular problem for us as we have a dog who bangs through it and takes the door with her!
A particularly useful feature of this flap was the ability to be able to purchase spare doors and fit them ourselves. This meant that when we forgot and had the cat flap open and the dog loose near it - replacement was painless. I realise that this is a particular problem relevant to people with dogs of cat size. Otherwise we find the flap excellent and easily replaced when needed.