High Sensitive & Quick Responsive: Build-in Carbon Monoxide Detector Chip and the electrochemical sensor, Enough to detect odorless invisible and deadly carbon monoxide in the air, Quick reaction to save your life in the first time when fire hazard occurs. ENERGY SAVING: 2 * 1.5V AA battery powered CO detector (not included),The alarm sound pattern is 4 beeps every 5seconds for the first 4 minutes. In 4 minutes, it will change to 4 beeps ever minute to save the battery, Low Current consumption, Ultra-long Standy time. Sound Alarm Warning: When detecting that carbon monoxide reaches a dangerous level,the red LED will flash,You can use the digital display to see the current CO concentration and the status of the machine's battery level.and the alarm mode will issue an 85 decibel alarm to protect your familys life and property from the carbon monoxide detector. NOTE: IN NORMAL CONDITION, LCD IS NOT LIT FOR SAVING ENERGY,ENTER THE STANDBY STATE) Alarm Standard: The alarm time depends on the carbon monoxide concentration level, 50ppm, alert within 60 to 90 minutes; 100ppm, alert within 10 to 40 minutes; 300ppm, alert within 3 minutes. Note: Pls test the detector first, and do not use gas blow the hole directly when you test it. Easy Installation & Widely Used: Requires no rewiring,Battery operated device Can be easily installed and maintained without the need for an electrician,Easy to mount on any wall or ceiling with the included mounting accessories,You Can Hear the low power alarm When the Power is Close to Run out, and wont Miss the Chance to Change the New Battery.Used for bedroom, kitchen, living room and any other area.