Well, these door alarms work wonderfully and are easy to use BUT one of the two I ordered has broken when I simply went to put it on the door handle. I don’t think I’ve had it out of the box for more than 3 minutes. If you get a “good one” you’re grand, but clearly there are some faulty ones so it looks like I’m stumping up £500 for a faultless system after all. You can’t have a security solution that “might” work. Not reliable - a shame! The other one seems great. Oh well!