What a silent alarm does and does not prove · review
One unit for smoke and CO, with First Alert’s Precision Detection to reduce cooking false alarms.
First Alert states 2-in-1 protection, Precision Detection, an end-of-life warning and a test/silence button.
A home CO alarm is built to hold off at low levels: see our UL 2034 page for the alarm windows. A silent alarm does not prove the air is free of CO.
If the alarm sounds, get everyone outside to fresh air and call 911 or the fire department from there. Check the replace-by date, and follow the manual and your local code on where to mount it.
| Detects | Smoke and carbon monoxide |
|---|---|
| Power | Battery |
| Sensor | Ionization in the table |
| End of life | Warning signal |
| Size | 5.6 x 5.6 x 2 in |
| Amazon reference | B0CY3BZCX9 |
| EAN | 0029054022950 |
Only where its manual allows, and your local code still sets how many you need.
No, it is battery operated.
8.1/ 10
A tidy combined alarm.
This model is listed on Amazon.com, at ≈ $37 at the last reading. Listed is not the same as in stock: availability changes daily, and the buy box shows the live price.
Details checked on November 1, 2026.
A hallway where one combined alarm is the practical choice.
Amazon reports what buyers took in the month before this page was last checked: at least 10,000.
The figure is a floor, rounded by Amazon, — it says what buyers picked, not what a maker claims.
Specifications: the manufacturer sheet for wood heating equipment and the matching Amazon product page. Prices, ratings and availability: read on Amazon.com from a New York address. Every figure on this page names its source.
Same shelf, closest price — what the same spend else heats.
2 AA batteries · electrochemical · 85 dB · LEDs · Event Memory · portable
A small AA alarm with Event Memory, which records the last time it detected CO, with 2,356 ratings at 4.7 out of 5.
Best for: A cabin or travel alarm, or a second alarm at home.
≈ $25
plug-in · 9V backup · digital display · 85 dB · 3rd edition
The older Kidde plug-in with a digital display, a 9V backup and 28,356 ratings at 4.7 out of 5.
Best for: A buyer who trusts a long record over a newer model.
≈ $70
plug-in · 9V backup · 85 dB · electrochemical · 3-pack · 7-year limited warranty
A 3-pack of plug-in alarms with 9V backup and a 7-year warranty, which covers a whole floor plan.
Best for: Covering each level and bedroom at once.
≈ $71
The price beside each product is fetched as this page opens, and it is the only figure here that is current. Any amount written into the prose was read once, on the day that sentence was written, and nothing has refreshed it since.
