The cat flap arrived quickly in the post and after reading all the instructions I had a go at installing. Remember to programme before installing. The most difficult part for me was cutting out the hole in my UPVC door, though probably because it was my first time using a jigsaw. Once I had the hole cut it was relatively easy to put both parts of the catflap together and complete the job. I have put the door in training mode for a few days so that my two cats can get the hang of it. So far so good. They seem happy that they can come and go as they please and no longer have to ask to be let out. I would recommend this cat flap