First Alert Combination Smoke & Carbon Monoxide Alarm, Battery-Operated Detector with Slim Profile Design, SMCO200, 1-Pack

This First Alert combo smoke and carbon monoxide alarm does exactly what it’s supposed to do — protect your home — and does it without being bulky or obnoxious. The slim design is a big win. It sits flush and clean on the ceiling or wall and doesn’t look like a giant plastic UFO hovering over the room. Setup was quick and easy, the battery operation means no wiring headaches, and it feels solid and well-built. Knowing it’s watching for both smoke and carbon monoxide is huge peace of mind, especially at night or when you’re not home. Basically, it’s one of those products you hope never has to prove how well it works — but you’re really glad it’s there just in case. Reliable, simple, and smartly designed. Exactly what a safety device should be.

These combination detectors are really good and worth every penny. I had one prior to this one same brand and unit but disposable with a built-in battery. I like this one because I can replace the batteries, it uses 2 AAA batteries because it's so thin and will let you know when the batteries are low.

It’s a good buy and name brand quality.

Solid smoke and CO2 alarm. Only 4 because it has no sticky tape on the back vs drilling into the ceiling

The base is slightly larger than an earlier model so I needed to screw in an extra anchor hole. One I could reuse.

The tabs on the alarm body and the mounting body are too thick and won't allow them to twist into the lock position. The 2 pieces come unattached in the package so you don't discover it won't work until the last steps of installation. Try it before you install. FYI: I was able to re-use the existing First Alert mounting body and install the new alarm body to it.

Luckily we haven’t seen how it would work in a fire. However, it doesn’t go off randomly so that’s good. It didn’t fit where my previous smoke detector was hard wired to ceiling so we just put it somewhere else.

The size is perfect.