Bests & Worsts Reviews from Amazon

I would have given this good reviews, because it is easy to use and I think would probably work correctly, but after having it only a couple of months one unit already started beeping with the ERR code. That code means end of life. The units say they have a 7 year life after start of use. Well, 2 months is far from 7 years, but I checked the manufacture date and it was made in October of 2006, so Amazon is selling 10 year old detectors. and apparently manufacture date does matter, not just start of use.