I have bought three of these in the last 2 years.The first one lasted a couple days before it started cherping my dog cant stand it. the last two i bought this year one is a dual alert , so far it is Ok..The other was up a few days,then it started to make cherps. I called the company and they sent a new one at no charge, it has started to cherp at 4 in the morning for no reason for 10 year life span that is not so good. going to find different brand. User's recommendation: call fire dept. for there recommendation on alarm.