Feature: 1. This product detects carbon monoxide through the air intake. 2. When the concentration reaches a certain value, a 90 decibel alarm sound and warning light will be issued (the interval is different for different concentrations). 3. With LCD display real-time display density (less than 30PPM will not display). 4. Powered by 2 AAA batteries (not included), low power consumption, sustainable standby for about 1 year. 5. Easy to install and improve the safety of the home. Specification: Condition: 100% Brand New Item Type: CO Sensor Color: Shown as Picture Material: ABS Detection Angle: 360 ° Detection Distance: Approx. 15m/49.2ft Installation Method: Wall-Mounted Scope Of Use: Bedroom, Living Room, Bathroom, Kitchen Power Supply: 2 x AAA Batteries (not Included) Alarm Mode: Sound + LED Indicator Alarm Volume: 90 ± 5db. Package List: 1 x Carbon Monoxide Alarm1 x Screw Bag1 x Instructions Note: Cannot be used for natural gas and liquefied petroleum gas detection.