SOUND AND LIGHT ALARM -- When a dangerous level of carbon monoxide is detected the red light will flashes and a loud alarm pattern will sound-Loud 85 decibel carbon monoxide alarm with red light flash to protect your family's life and property safety from CO detector CO CONCENTRATION DISPLAY -- Digital display displays the level of carbon monoxide the unit is sensing, You can keep abreast of the concentration of CO from the Sunnec carbon monoxide alarm ENERGY SAVING -- Operated by 3 x 1.5V AAA Batteries, You can hear the alarm when the power is low, don't worry about when to replace the battery APPLICATION CO DETECTOR PLACE--This carbon monoxide detector suitable for all where it is possible to produce carbon monoxide, such as your home kitchen, bedroom, bathroom, hotel, or you are in the barbecue time, your parking garage