FIRST ALERT CO400 Carbon Monoxide Detector 2-Pack – Battery Operated, No Outlet Required

Overview

Meet the FIRST ALERT CO400 Carbon Monoxide Alarms, a dependable, battery-powered safety solution designed for homes without requiring electrical wiring. Each alarm runs on a standard 9-volt battery, so you can place protection wherever it’s most needed—even during power outages.

Technology and reliability you can count on

Equipped with an electrochemical CO sensor, the CO400 targets carbon monoxide with proven accuracy. The sensor is engineered for longevity, providing up to five years of sensing capability before replacement is recommended, which helps reduce maintenance frequency.

What you get in this 2-pack

• Two battery-operated CO detectors ready to install with no outlet required
• One-button test and silence control for quick checks and quieting alarms
• Audible 85-decibel horn paired with clear visual indicators
• End-of-life indicator to signal when it’s time to replace the unit
• Optional wall mount and included mounting hardware for flexible placement
• UL listed with a 5-year limited warranty for added peace of mind

Placement for comprehensive coverage

CO disperses evenly in enclosed spaces, so consider placing units on every level and in sleeping areas to maximize early warnings. The compact, unobtrusive design blends into bedrooms, living rooms, kitchens, and spaces near fuel-burning appliances.

Practical use and ongoing benefits

• Alerts you to elevated CO levels with a loud alarm that can wake occupants
• Continues monitoring during power outages thanks to battery operation
• End-of-life signal helps you know when it’s time to replace the unit
• Simple maintenance and testing support confidence in everyday safety routines

Why consider this 2-pack

The 2-pack provides practical coverage across a home, with two independent alarms that operate without electrical wiring. Each unit uses a reliable sensor and a simple user interface to support everyday safety checks.