--- product_id: 2536037 title: "Battery Carbon Monoxide Alarm | CO400" brand: "first alert" price: "A$46" currency: AUD in_stock: true category: "First Alert" url: https://www.desertcart.com.au/products/2536037-battery-carbon-monoxide-alarm-co400 store_origin: AU region: Australia --- # Battery powered, works during power outages 85 dB loud alarm for instant alert 5-year sensor life & replaceable 9V battery Battery Carbon Monoxide Alarm | CO400 **Brand:** first alert **Price:** A$46 **Availability:** βœ… In Stock ## Summary > 🚨 Stay ahead of danger with the CO alarm that never sleeps! ## Quick Answers - **What is this?** Battery Carbon Monoxide Alarm | CO400 by first alert - **How much does it cost?** A$46 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.com.au](https://www.desertcart.com.au/products/2536037-battery-carbon-monoxide-alarm-co400) ## Best For - first alert enthusiasts ## Why This Product - Trusted first alert brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Effortless Setup:** No installation neededβ€”place it anywhere or use the optional wall mount. - β€’ **Trusted Longevity:** 5-year sensor life backed by a 5-year limited warranty for peace of mind. - β€’ **Instant Loud Alert:** 85-decibel alarm cuts through noise to keep your family safe. - β€’ **Power Outage Proof:** Battery operation ensures continuous protection even when the lights go out. - β€’ **Unmatched Accuracy:** Electrochemical sensor detects CO with precision, wherever you place it. ## Overview The First Alert CO400 Battery Carbon Monoxide Alarm features a highly accurate electrochemical sensor with a 5-year lifespan, powered by a replaceable 9V battery to ensure continuous monitoring even during power failures. It emits a loud 85 dB alarm when dangerous CO levels are detected, requires no installation, and includes a 5-year limited warranty. UL listed and trusted by millions, it’s designed to protect your home and loved ones from invisible carbon monoxide threats. ## Description Product Description The First Alert CO400 carbon monoxide alarm uses an electrochemical sensor the most accurate technology available. The permanent sensor lasts up to 5 years. It is powered by a 9V replaceable battery giving you peace of mind even during power outages. The test/silence button silences the alarm and allows you to test its functionality. The unit monitors and re alarms if carbon monoxide level persist sounding a loud 85 decibel horn. No installation is required and the attractive design allows the unit to be placed anywhere you need it. It includes an optional wall mount with no outlet required. An audible and visual battery signal alerts you to replace the battery. Pull down action chart has convenient guide on what to do if an alarm sounds. 5 year limited warranty. Ul listed. desertcart.com Carbon monoxide (CO) is the leading cause of accidental poisoning deaths in America, yet many people don't know they are suffering from CO poisoning until its too late. Since symptoms of CO poisoning are like the flu, you might not even know you're in danger at first. That's why a carbon monoxide alarm is an excellent way to protect your family. It can detect the CO you can't see, smell or taste in the air. The First Alert CO400 carbon monoxide alarm uses an electrochemical carbon monoxide sensor-the most accurate technology available. The permanent sensor lasts up to five years. It is powered by on 9V replaceable battery giving you peace of mind even during power outages. The test/silence button both silences the alarm and allows you to test its functionality. The unit monitors and re-alarms if carbon monoxide levels persist sounding a loud 85-decibel horn. No installation is required and the attractive design allows the unit to be placed anywhere you need it. It includes an optional wall mount with no outlet required. An audible and visual low battery signal alerts you to replace the battery. Pull down action chart has convenient guide on what to do if an alarm sounds. 5 year limited warranty. UL listed. --Bree Norlander P.when('A').execute(function(A) { A.on('a:expander:toggle_description:toggle:collapse', function(data) { window.scroll(0, data.expander.$expander[0].offsetTop-100); }); }); Manufacturer Contact Information 1 (800) 323-9005. See more ## Features - Keep your family safe with this easy to use, battery operated carbon monoxide alarm; Battery powered alarms provide continuous monitoring of CO levels, even if there's a power failure - Features an advanced electrochemical carbon monoxide sensor that accurately detects carbon monoxide levels, no matter where the detector is placed in the room.The alarm sequence should last 5-6 seconds. If it does not alarm, make sure fresh batteries are correctly installed, and test it again. If the unit still does not alarm, replace it immediately - A loud 85 decibel alarm sounds when CO levels reach dangerous , Battery Replaceable - Yes - To ensure complete protection make sure to place one on each level of your home and in each bedroom - 5-year limited warranty; Equipped with end of life signal chirp, so you know when it’s time to replace the unit for safety - All first alert CO alarms are rigorously tested to meet UL standards - First Alert has been the most trusted brand in home safety since launching the first residential smoke alarm in 1958 (Based on a First Alert Brand Trust Survey in February 2018) ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B000N8OYXI | | Alarm | Audible | | Best Sellers Rank | #319 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #4 in Carbon Monoxide Detectors | | Brand | First Alert | | Built-In Media | Alarm; Mounting Bracket; User Manual; 9V Battery | | Color | White | | Customer Reviews | 4.6 4.6 out of 5 stars (21,862) | | Enclosure Material | Multi | | Global Trade Identification Number | 00029054000699 | | Item Dimensions D x W x H | 1"D x 5"W x 3"H | | Item Type Name | First Alert CO400FF Battery Powered Carbon Monoxide Alarm | | Item Weight | 11.2 ounces | | Manufacturer | First Alert | | Manufacturer Contact Information | 1 (800) 323-9005. | | Manufacturer Warranty Description | 5 Year Limited Warranty | | Mfr Part Number | CO400 | | Model Number | CO400 | | Number of Items | 1 | | Operating Humidity | 10-95% RH | | Power Source | Battery Powered | | Product Style | Battery Powered | | Sensor Type | Electrochemical | | UPC | 029054000699 | | Unit Count | 1 Count | ## Product Details - **Alarm:** Audible - **Brand:** First Alert - **Color:** White - **Global Trade Identification Number:** 00029054000699 - **Item Weight:** 11.2 ounces - **Operating Humidity:** 10-95% RH - **Power Source:** Battery Powered - **Product Dimensions:** 1"D x 5"W x 3"H - **Sensor Type:** Electrochemical - **Style:** Battery Powered ## Images ![Battery Carbon Monoxide Alarm | CO400 - Image 1](https://m.media-amazon.com/images/I/51RBX7hitxL.jpg) ## Available Options This product comes in different **Pattern, Size** options. ## Questions & Answers **Q: Has anyone else received the CO400 with one 9 volt battery instead of the two AA batteries listed in description and on picture of packaging display?** A: Yes, Received the 9-Volt battery version. I live in California. I'm not a lawyer but my research shows that in California Smoke detectors and Combo Smoke/Carbon detectors must come with a 10 year lifespan battery. This law does not seem to apply to devices that only detect Carbon Monoxide like that one for sale here. **Q: Why can't this be purchased in or shipped to California?** A: I live in California. Yes, I received the 9-Volt battery version. I'm not a lawyer but my research shows that in California Smoke detectors and Combo Smoke/Carbon detectors must come with a 10 year lifespan battery. This law does not seem to apply to devices that only detect Carbon Monoxide like that one for sale here. **Q: the package picture shows 9-volt, but sounds like it is a crapshoot on what they will send you. which is better and lasts longer, 2AA or 1 9V? I hate taking out and putting in 9v batteries. so many to choose from. would prefer plug-in but would be too low.** A: I bought a package of AA batteries because this item description said it takes 2 AA. It does not. It takes (and comes with) one 9V. This is model CO400. **Q: Red light is on. Is that normal? Tested and it chirps with test. Also checked battery.** A: YEs, red light is normal. If red light blinks - read manufacturer's guide in link below. https://www.brkelectronics.com/pdfs/2017/10/23/803bf30c.pdf ## Frequently Bought Together - First Alert CO400 Carbon Monoxide (CO) Detector, Battery Operated Alarm, 1-Pack - First Alert CO605 Plug-In Carbon Monoxide Detector with Battery Backup , White - Kidde Carbon Monoxide Detector, Battery Powered CO Alarm with LEDs, Test-Reset Button, Low Battery Indicator, Portable --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.com.au/products/2536037-battery-carbon-monoxide-alarm-co400](https://www.desertcart.com.au/products/2536037-battery-carbon-monoxide-alarm-co400) --- *Product available on Desertcart Australia* *Store origin: AU* *Last updated: 2026-08-27*