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Availability:
Only 4 left in stock, order soon!
Arrives
May 2 – May 5
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Size: 3-Pack
Style: Precision Detection
Pattern Name: SMI100
Features
- First Alert's Precision Detection advanced sensing technology complies with new industry standards to reduce cooking nuisance alarms and provides early warning in the event of a home fire emergency
- Battery-operated alarm allows for easy installation and maintenance
- Front access battery compartment makes for easy battery replacements
- End-of-life warning lets you know when its time to replace the alarm
- Test/silence button for efficient testing to ensure alarm is working properly
Description
The First Alert SMI100 Battery-Operated Smoke Alarm is equipped with First Alert's Precision Detection advanced sensing technology and meets new industry standards. This battery-operated smoke alarm is easy to install and the front access battery compartment makes for easy battery replacements.
Brand: First Alert
Style: Precision Detection
Power Source: Battery Powered
Color: White
Item Weight: 0.6 Pounds
Sensor Type: Ionization
Number of Items: 3
Manufacturer: Resideo
UPC:
Power Source: Battery Powered
Sensor Type: Ionization
Product Style: Precision Detection
Color: White
Item Weight: 0.6 Pounds
Brand: First Alert
Model Number: SMI100
Manufacturer: Resideo
UPC: 029054022417
Item Type Name: Smoke Alarm
Built-In Media: 9V Alkaline Battery
Unit Count: 3.0 Count
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
May 2 – May 5
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
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Similar Products
Top Amazon Reviews
Size: 2-Pack
Style: Precision Detection
Pattern Name: SMI100
I recently purchased the First Alert SMI100 smoke alarms and I’m really happy with them. Installation was incredibly easy since they are battery operated, so there was no wiring needed. I had both alarms mounted in just a few minutes. The design is simple and clean, and the front battery compartment makes it easy to change the battery without taking the whole unit down. I also like the test/silence button on the front because it makes testing the alarm quick and simple. The alarm itself is loud enough that you would definitely hear it throughout the house, which is exactly what you want for safety. The detectors use updated sensing technology designed to give early warning of fires while reducing nuisance alarms from things like cooking smoke.Overall, these smoke alarms give me peace of mind knowing my home has reliable protection. They were affordable, easy to install, and work exactly as expected. I would definitely recommend them to anyone looking for a simple and dependable smoke alarm.
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Reviewed in the United States on March 4, 2026 by Steven
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
So far so good, we've had these fire alarms for about a year now and the one near the kitchen we replaced the batteries about 6 months ago, and the other one we just did for the first time. The one near the kitchen has been triggered a few times due to various baking mishaps so that makes sense I guess, definitely loud enough to wake you if necessary. Its a bit of a pain to change the batteries but that's life. Seems to be reliable and that's all I really care about. Install was simple enough.
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Reviewed in the United States on April 9, 2026 by Elizabeth Sweet
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
These aren't interconnected, and are powered by battery only. But they do the job as described and are a lower cost option to replace the more costly interconnected "wired" models.
Reviewed in the United States on April 5, 2026 by Kampers
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
A great, cheap option for a smoke detector! Installed onto the wall super easy. One issue, is the battery compartment can catch when trying to install the battery, but a little pressure and it clicks into place (without breaking any plastic, thankfully).
Reviewed in the United States on March 1, 2026 by Corey Holloway
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
This First Alert smoke alarm is clearly the standard. Works reliably, is a powerhouse in a small size. It can be installed easily with a simple nail or screw without using the wall attachment materials included. It has a very loud piercing notification signal which is exactly what I needed to wake kids out of bed and get them started on how I have trained them if there is a fire. This unit was a replacement for a unit I have had for nearly 10 years. These smoke alarms are reliable.
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Reviewed in the United States on March 30, 2026 by I. Redman
Size: 2-Pack
Style: Precision Detection
Pattern Name: SMI100
I just installed these 2 First Alert smoke detectors, so I can’t give you a long time use review, but I’m happy with my purchase. These replaced two 10 year-old similar First Alert smoke detectors that had reached their expiration date. I was very pleased with those, which is why I looked for the same smoke detectors. I couldn’t find the exact same ones, so I replaced with these, which look similar and are basic like the first pair. Although the size of the new ones are a little bit smaller than the ones they replaced, I was pleased to find that the new brackets fit the 2 screws I already had in the walls from the old ones. I was concerned that I would be patching and drilling, but I didn’t have to, so installation was easy peezy. The other thing that is different on the new ones is that the batteries are 9 V versus the AAs for the old ones. I prefer AAs because it’s a battery that I always have around the house and they are easy to come by and inexpensive, relatively speaking. However, the new detectors came with batteries, so I don’t have to worry about replacing them for another year.
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Reviewed in the United States on February 1, 2026 by Newleaf
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
I've been using this brand for decades and I'm glad they took things to a little higher level for the most basic even though it costs a little more . For some reason the ones I have that were the old basic unit would last about 3 years then start beeping like the battery was dead even with a new battery , thus needed to be replaced . This unit is easier to blow off the sensor and hopefully that'll help it last longer . Nothing more annoying than that irregularly timed beep at oh dark thirty and not knowing which one it is because of the irregularity of when it beeps . I have a smoke detector in every bedroom, laundry , kitchen, den and hallways for a total of 8 in the home. Not knowing which one needs attention sucks . This one did need for me to change the frame it fits in but the screws stayed in the same spots so it was super quick to change out .
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Reviewed in the United States on April 11, 2026 by Stephen Elmore
Size: 1-Pack
Style: Precision Detection
Pattern Name: SMI100
It works I don't like that the light doesn't stay lit all the time to let you know it powered. But it works time will tell how good it is?
Reviewed in the United States on December 23, 2025 by Kevin Wicki