Our carbon monoxide detection alarms are UL 2034 tested. UL Testing Institute is the most authoritative in the United States, and it is also the industry standard for electronic products in the United States, and it has been approved by the US federal agency to perform tests, so rest assured to buy Features of carbon monoxide alarm: 1: Easy to install, very simple 2: The backlight display of the display screen, when the danger comes, you can immediately see the degree of co on the display screen, and make a better judgment 3: Test/Reset button 4: Low battery indication 5: Power saving function Information About Carbon monoxide Detector Power Supply: 3* AA Size 1.5V batteries(Battery not Included) Sensor type: Electrochemical CO sensor Standby Current: 120uA(with LCD) Alarm Current: 40mA Alarm tone: 85 decibels Operation Ambient Condition: 5~400C,25~85%R.H Detecting level range: 000-999PPM Error: +/-10% Size:3.937?inch?*3.937?inch?*1.377?inch? Weight:80g Package Include: 1 x Carbon Monoxide Alarm 2 x Screws?2 x Nuts 1 x User Manual Notes: 1. The carbon monoxide alarm is designed to detect carbon monoxide gas. Not suitable for smoke detection or any other gas detection. 2. Before installing the carbon monoxide detector, peel off the back cover of the carbon monoxide alarm product, and then put the battery into the carbon monoxide detector. (battery not included) The carbon monoxide detector alarm continuous monitoring of Carbon Monoxide levels to keep your family safe. Operated by 3 * 1.5V AA batteries (not included),portable and easy installation,no need for socket, not affected by power failure, can be installed anywhere! Fast and Accurate Detection?The carbon monoxide detector is built-in advanced electrochemical CO sensor that provides precision alarms for fast and accurate detection of carbon monoxide levels. When the carbon monoxide concentration exceeds the specified value, an alarm warning of more than 85 decibels will be issued. To ensure complete protection, be sure to place one on every floor of your home and in every bedroom. LCD Digital Display and LED Indicators?Simple to use,with a single test/reset button,when a dangerous level of carbon monoxide is detected the red LED will flashes and a loud alarm pattern will sound--Loud 85 decibel alarm with LED Flash. Portable and Easy to Install?The carbon monoxide detector is easy to install without rewiring. It can be mounted on wall or ceiling?Please refer to the instruction manual for the specific location of the carbon monoxide sensor installation?, This CO detector includes mounting screws and anchors,. It is an ideal carbon monoxide quotation device for home use Alarm standard: 50ppm, alert within 60 to 90 minutes; 100ppm, alert within 10 to 40 minutes; 300ppm, alert within 3 minutes. Note: When you test the detector, please do not use gas blow the hole directly. Package Includes? 1carbon monoxide detector,1manual, 2 screws, 2 anchor plugs.If you meet any issues with Carbon Monoxide Detector, just contact us via or Amazon question message, We will consistently spare no effort to provide good service and experience for every customers! Carbon monoxide alarm installed battery status(not included battery): When the carbon monoxide detector is installed with a battery, the product will emit a "beep" alarm sound and then enter the standby state. During the standby process, the green light will flash once every 30 seconds, which means the product is normal Work