Features: The carbon monoxide with a digital display that can sensitively detector the concentration of carbon monoxide. The alarm sound reaches 85 decibels, a super-strong alarm device. The Co alarm detector adopts a high-precision sensor that can alert you to the dangers of carbon monoxide. Protect your life safety. Powered by 9V dry battery(include), easy to install. Battery lifetime up to 1 year. The equipment has a fault self-checking function. When a fault occurs, the fault light will always be on to remind the normal operation of the equipment. Smart sensor sensitivity setting, 50PPM 10-40 minutes alarm, 100PM alarm immediately, no need to worry about the alarm falsely. If there are any problems, please contact our store in time. We will give you a satisfactory solution. Thank you for your understanding.