It's been a long time that hubby is thinking of installing smoke detectors at home for security purposes. However, it was just yesterday wherein he was inspired to do it. I am very grateful knowing that despite of not being a handyman himself, still he is trying his best to do it alone. There were moments that he got irritated especially that installation manual are not often apparent or clear. lol* Anyhow it's a good device, the only thing that's regrettable is the fact that it doesn't have a rechargeable batteries on it!