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The First Alert CO400 Carbon Monoxide Alarm utilizes an electrochemical carbon monoxide sensor that lasts for up to five years to detect carbon monoxide. This carbon monoxide detector is battery powered, making it portable and easy to use anywhere, even in the event of a power outage. When carbon monoxide levels become elevated, a loud 85-decibel alarm alerts you to the threat.
The Most Accurate CO Sensor Available
The First Alert Carbon Monoxide Alarm uses an advanced electrochemical CO sensor to detect elevated carbon monoxide levels. When CO is detected, the carbon monoxide detector sounds an alarm to warn you of the threat.
Comprehensive Warning Features
When carbon monoxide levels rise, the carbon monoxide detector sounds an 85-decibel siren that is designed to wake even the soundest of sleepers. A low-battery light and alarm alert you when battery power is running low, and an end-of-life timer lets you know when the device should be replaced. Each CO detector lasts approximately five years.
Simple and Easy to Use
The First Alert Carbon Monoxide Alarm is easy to set up. Simply insert the battery, and the CO detector will start to monitor your space for carbon monoxide. There are no complicated displays or settings to navigate. A single button silences the alarm and tests the CO detector. A pull-down action chart instructs you of what to do if the CO alarm goes off.
Where To Place Carbon Monoxide Alarms: One on every level of the home and one in each sleeping area.
First Alert Carbon Monoxide Alarm CO400
Actual battery service life depends on the particular design of your smoke or carbon monoxide alarm and the environment in which it is installed. All kinds of alarm batteries specified in the user's manual are acceptable replacement batteries. Regardless of the manufacturer's suggested battery life, you MUST replace the batteries immediately once the unit starts "chirping" (the "low battery warning"). It is recommended that you change the batteries in your alarms when you change your clocks for daylight saving time. Also consider replacing your current alarms with 10-Year Life Alarms that never require a costly battery replacement for the ten year life of the alarm. This 10-Year series is available in smoke, carbon monoxide and combination alarms.
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Average score based on 168 reviews
- Reviewed: 11/08/2021 by Darlene S
First Alert Alarm
Replaced the original with the same type. Fast shipping and easy set up. Will replace with same when needed. Love it!
- Reviewed: 09/29/2021 by SHIRLEY W
As promised, order arrived quickly, in mint condition. and with clear instructions as to how to set up and use it. The alarm worked perfectly the first time, and I have no doubt it will last as long as the one it replaced.
- Reviewed: 05/17/2021 by George N
Couldn't Have Been Easier
I recently had to replace my First Alert CO detector. I decided to buy the same Model#. When did a Google search for that item, I was pleasantly surprised to find that the First Alert direct price was the lowest, and shipping was free. The whole ordering process was very easy, and I received the item quickly.
- Reviewed: 03/02/2021 by Tom Rubenstein
Basic Battery Operated Co2 Alarm-CO400
Ordered product directly for First Alert website...easy to navigate and simple order process. Received product within 3 days. Directions for install were thorough and straightforward.
- Reviewed: 01/25/2021 by James D Stewart
Fast and easy
I have ordered from this site before. It is easy to order and delivery is fast. Product arrived and is as described on the web site. Good product.
- Reviewed: 12/17/2020 by Lisa Andrade
Very easy to order and fast service!
- Reviewed: 12/01/2020 by Karen Eskew
Always use first alert products. Very trustworthy and safe.
- Reviewed: 11/30/2020 by Steve K
Works fine and easy to install
- Reviewed: 10/10/2020 by Philip Davis
Fast delivery, packaged well, exactly as expected.
- Reviewed: 08/04/2020 by Bernard Dube
My order came in and seems to be operating well. Thank you