【2 In 1 Protectio】Home Alarm has two built-in sensors that display smoke and carbon monoxide (CO) concentrations on a large LCD screen. This prevents being affected by the concentration of carbon monoxide and smoke in the surrounding air. Reminder: During the test, put the alarm in a sealed bag and test it with an appropriate amount of carbon monoxide and smoke.【Super Alert】When the carbon monoxide level exceeds 300ppm, an alarm will sound, the red light will flashes and the buzzer sounds every 5 seconds. The valve should be immediately closed and doors and windows opened to allow indoor air to circulate. If a smoke concentration above 0.1% db/m is detected, an alarm sounds, the blue light flashes, and the buzzer always sounds an alarm volume above 85 dB.【Sensitive and Fast】Carbon Monoxide Smoke Detector Equipped with an electrochemical CO sensor and an advanced smoke sensor for accurate detection of carbon monoxide and smoke hazard levels, if the detected concentration exceeds the range, the product reacts quickly and gives you an immediate alarm sound of 85 dB. Until the amount of ambient gas drops below the alarm set point.【Ultra Low Power Consumption】Gas Detector Display will be in standby mode during normal working. Only the light works and the green light flashes once every 30 seconds. The CO detector consumes a small amount of power in standby mode and the battery standby time is six months. Also Low battery alert function: when the battery is low, the red light flashes once every 10 seconds and the LCD displays "Lb".