So I picked these for my house and I decided to get one for the alarm in my room since the one in my room was failing. It turned out to be that it wasn’t the hardwire interconnecting that was bad. The i4618 alarm itself wouldn’t react to smoke or set the others off so I’m EXTREMELY glad that I replaced it. As you can see before the video I removed it and the video when I removed it was a fail because the mounting bracket fell and hit my phone and my phone fell off of the ceiling fan blade so I had to retake the video review and I decided to just install the new alarm on video. I decided to make a KZread short where I sprayed the new alarm with smoke and was seeing if it would set it off and set off the others in my house and it did so it passed my test. I will be replacing the others in my house later this week or next week as I noticed the one in the hallway outside my room didn’t set the others off when I pressed the test button on it shortly after made this video. I had forgotten that the BRK 4120B smoke alarm that used to be on the ceiling in my room burned the ceiling so there are burn marks but luckily that isn’t from the i4618. I remember seeing a melted BRK First Alert hardwire harness and burn marks when the electrician replaced the alarm with the i4618 back in 2013. I decided to just go ahead and replace all the alarms because the time changed recently and people on NBC news said that you need to replace your smoke alarm batteries and if your smoke alarm is past the manufacturing date or installation date then you should go ahead and replace the alarms themselves and another reason is I had a few of the i4618’s fail on me and the i4618 in my room wouldn’t react to smoke and it wouldn’t set the others in my house off when I pressed the test button so that’s why I decided to choose this one that you see here to be replaced first. I wanted one that would wake me up if there was a real emergency. So basically that means if a smoke alarm in a different room activates then the one in my room will go off along with the rest in the house because my smoke alarms on my wall aren’t interconnected with the rest of the smoke alarms in my house.