Have 2 smoke detector ordered in spring 2013, hoping to be backed up with no problems the next 10 years. Far from it, in a few weeks both smoke detectors are now broken, no smoke alarm was triggered effect, battery? This can not replace themselves known. The smoke alarm was defective 1. withdrawn traveled refunded amount, the 2nd is currently on the way back to Amazon, should also be reimbursed, therefore, no great loss.