FIRST ALERT BRK SC9120FF Hardwired Smoke and Carbon Monoxide (CO) Detector with Battery Backup, 1 pack , White

Easy to install and plugs into my existing First Alert wiring. Hopefully these last longer than the builder grade one's I've been replacing.The base plate that these alarms twists into wasn't compatible with my existing units, which was wishful thinking since it's the same brand, but it was easy enough to loosen the screws, remove the prior and spin these on.Two of the three sets I ordered didn't come with the yellow protective bonnets pre-installed, which isn't a big deal but would have been a nice touch to know they've been protected from dust or other environmental contaminants prior to install.

Was able to replace all my smoke detectors with smoke and CO2 detectors. You should replace your smoke detectors every 10 years. Mine were clearly original to the house (1993). They work seamlessly with my other Smoke/CO2/Flasher alarms. They are really easy to install, and I'm glad to have the house updated.

Bought a new house and they clearly hadn't changed the detectors for way over 5 years.This was a good deal buying in bulk. Hardwired detectors should be preferred over battery operated ones. You will need 9V batteries for when the power goes out though.Be sure that the connector you have matches the one on on these First Alerts. You can get or alter the existing ones to work with these connectors if you have a mismatch if you really want. These come with wires and the other plug end so that you can snip the wires on your existing clip and replace it with a new connector if you need to. I generally don't like doing that but for something you only do once every 5 years it's not a big deal. Luckily my existing hardwired connector from the outlet fit the plug on these detectors.First Alert is a top tier brand and it'll do great at detecting smoke. Carbon Monoxide is trickier to detect across the board, especially when the detector is on the ceiling so by the time the alarm is going off you've got a lot of carbon monoxide in your home but it still gives you enough of a warning to where you can grab your family and get out the house (preferably opening a window on the way out if you have pets especially).It comes with a nice collar and frame so you don't have to install these over an ugly yellowing collar/frame from an old one. The twist to install/remove mechanism works well. The plug for the hardwired feature connects very strongly too. Sometimes it could be difficult to remove but honestly you won't have to until you replace the entire thing anyway. You can easily change the batteries without removing the clip connector from the wall.

Replaced the SC9120B after 3 chirps. They were installed in 2017. The manufactur date on these is 1/2025. Just need to replaced the old with the new, including bracket, piece of cake.

Ordered 6 of these to replace 10yr old previous model #9120B. Installing them was fairly easy. The base of the unit must be changed, but no problem as the screws and spacing of the screws was the same. Plugs for the wiring is the same also. Unplug the old unit and plug in the new detector. Easier said than done. Plugs are an EXTREMELY tight fit. I know some will have trouble here. My only real negative issue is that these new detectors are extremely bright when viewed at night. Not a problem in most spots, but having one in the bedroom bathes the area in a dim green light. It highlights everything. It even lights up a small spot on the floor. Troublesome when trying to sleep. Will work on making a "shade" to block the view without blocking the detectors function. It is a needed item and because of that I will "recommend".

Works great and comes with the wires, battery and mounting hardware too.

Quick delivery. Purchase these as replacement for 10 year old first alert alarms. Easy install. Fit the old collars perfectly. Replaced six units in about 15 minutes.

It was perfect!