BRK SMI100-AC Hardwired Smoke Alarm with Battery Backup, Contractor 6-Pack

Great product, great price, and great shipping!

Purchased these to replace my very old first alert smoke detectors. Easy to install and pull the tab to activate the battery that's included.

Replacing 20 year old original alarms with these. Connects to my existing wiring, so I didn’t need to use the wiring that came with it. I was hoping these would attach to the same mounting bracket I already had since they’re the same brand, but they don’t. Not a big deal and actually helpful since they’re slightly wider than the old ones and covered the old paint the painters didn’t get covered around it. All I had to do was loosen the screws, twist the old mounting bracket out and put the new one on in reverse order. Easy. I was surprised these came with the backup battery already installed, so now I can return the pack of batteries I bought. Just pull the tab out and they’re activated. Comes with a dust cover I guess if these are installed during construction to keep them protected from dust. I wouldn’t use it to paint over, because it won’t cover the bracket. I would recommend these from this well-known brand.

Good price and easy to install

I bought these to replace a set of Firex 120-1182B detectors that were installed with my house. The product title on Amazon says it's a First Alert 9120B6CP, but "9120B" is what's printed on the detectors. The extra "6CP" makes it confusing, IMHO. The new First Alerts are presently operating simultaneously with a few remaining Firex detectors that are still in the house. (2 are the 120-1182B models and one is a combo smoke and carbon monoxide detector.) I was able to install them as expected, but due to the various manufacturers' refusal to create a **standard** connector (even between Firex models and the Kidde "upgrades"!), installation was irritating. There isn't even a **standard* mounting ring/bracket. (And then there's the interconnection signal.) I had to pop off the detector, disconnect the electrical harness, loosen the mounting bracket's 2 screws and pop that off. Then, one wire at a time, I took off the wire-nut, swapped out the correct wire, and replaced the wire-nut. (You should probably shut off the power, but if you accept the risk understand enough about electricity, and are careful, you don't have to---and you avoid all of the "power lost!" chirps.) Then I just shoved the wires back into the box, put the new mounting bracket on, tightened the screws, connected the new detector and popped/screwed it on. Press the button, cringe at the piercing "test" chirp. Done. It took about 5-10 minutes for each one; easy-peasy. I had wanted to purchase the Kidde i4618 since it's supposed to be the "new model" for my existing stuff, however, due to lack of standards, and poor documentation, it's the same risk and effort to switch brands as it is to upgrade! In my perfect world, if I wanted to replace a smoke detector, I'd just buy a new one, pop the old one off the mounting bracket, disconnect it from the wiring harness, then work in reverse with the new one; the same wiring harness and mounting bracket would work regardless the brand or model. After all, the boxes in the ceiling are standardized and there's always 3 wires for hard-wired/interconnected smoke detectors. And if there's no standard, why have a harness at all? Why not just connect them with wire nuts like a dishwasher? I didn't go with the Kidde for 2 main reasons. (1) There's this "KA-F" adapter (more $$$) that is supposed to make it so you don't have to also swap out the pigtail connector. However, while various reviews on Amazon say that the KA-F adapter is the exact adapter I needed, the documentation on Kidde's site clearly indicates it's *not* compatible. And there are no clear pictures of all angles of the adapter to allow one to be sure if it would or would not work; in fact, I've found multiple pictures that say they are of the KA-F adapter, but the adapters look significantly different. (2) The other reason is that these First Alerts came with Eveready batteries, which helped me feel a bit more confident that I won't be woken up by a low-battery alarm in a month or so (like some reported with the Kidde i4618). They all work without setting each other off, however, pressing the "Test" button on the new First Alerts will not trigger any Firex, and the same vice versa. Since I have to replace everything in the house anyhow, it doesn't matter.

It fits well on my old BRK 9120B seats. So works great.

The delivery was overnight and what a relief. These smoke detectors were spot on. We had our former smoke detectors for over 20 years and thought maintenance meant changing the battery and vacuuming any exterior dust particles. Nope, it means one should replace it at least every 15 years. HD and many hardware stores can't stock all the various types of smoke detectors. I looked up the original product number on the old smoke alarm and it was a perfect match. The only item that had to be changed was the base of the unit didn't match the previous one. Everything else worked perfectly. 1. Don't use a regular 9 volt, we purchased the Eveready long life and they generally last 5 years. Date the battery before you place it in the detector. 2. Date your detector on the outside, so you know when to replace it. 3. If you have a detector that is older than 10 years, definitely replace it. The MFG warranties it for 10 years. After that you are on your own. 4. When the weather changes for the winter, that is when the batteries and the back up system will blow in the middle of the night, generally after 430am. The price was right, 6 alarms for a little over $100 with shipping and tax. Do yourself a favor and replace the alarm after 10 years. The alarm company told me this or I would have just changed the battery and had the alarm go off again.

My existing BRK 4120B Smoke detectors were 25 years old (Feb 2000) and generally pretty nasty looking. While over the last 25 years we always removed the detector(s) when painting, the base(s) didn't always get removed (I blame other family members for that). We just painted the spare room for the zillionth time and I decided to replace them all. I actually found out I should have replaced them 10 years ago! I was happy I didn't need to use the included power cable because the old detector's connector fix properly. If it wasn't for the paint (and discoloration) on my existing bases I could have reused those too! One thing I don't like is the LED Light on these 9120B. The 25 year old 4120B detector's had the LED light focused through a lens with little to no bleeding. These new 9120Bs, the LED light bleeds out all over the place from the speaker chirp vents. I decided to keep one set of instructions because the detector has different chirps/blinks for different issues. I also didn't realize there is a 8-hour chirp sleep when a battery dies. I am pretty sure my old 4120B didn't do this but I'd never had its instructions, so perhaps it did have that "8-hour sleep" feature? Which the battery dead chirp always happens at 3am!!!