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 buyFeatures of carbon monoxide alarm:1: Easy to install, very simple2: 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 judgment3: Test/Reset button4: Low battery indication5: Power saving functionInformation About Carbon monoxide DetectorPower Supply: 3* AA Size 1.5V batteries(Battery not Included)Sensor type: Electrochemical CO sensorStandby Current: <120uA(with LCD)Alarm Current: <40mAAlarm tone: 85 decibelsOperation Ambient Condition: 5~400C,25~85%R.HDetecting level range: 000-999PPMError: +/-10%Size:3.937(inch)*3.937(inch)*1.377(inch)Weight:80gPackage Include:1 x Carbon Monoxide Alarm2 x Screws,2 x Nuts1 x User ManualNotes: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)