Description The carbon monoxide (CO) detector is equipped with a high-precision and reliable long-life electrochemical CO sensor, which can quickly detect CO gas leaks and ensure safety L digital display shows battery status and real-time concentration of carbon monoxide in the air (ppm), when there is no CO gas in the surrounding air, the display shows 0 ppm The carbon monoxide alarm detector with self-test function automatically detects hardware faults such as internal circuits and carbon monoxide sensors in normal standby state, ensuring operation correct at all times Powered by 3 x 1.5V AA batteries (battery not included). A low battery warning reminds the user to replace the battery to ensure full protection. And easily mount to a wall or ceiling with mounting accessories in minutes