[2 in 1 Protection] The combined smoke and carbon monoxide detector is equipped with an electro-optical smoke sensor and an electrochemical CO sensor that operate independently of each other. It detects both smoke and co, making your home safer by providing the ultimate protection against two deadly threats..[Voice alarm] The e voice system can help you quickly understand the danger, orderly evacuation. Carbon monoxide (CO) alarm pattern is four quick beeps with voice “Warning! Carbon Monoxide, evacuate" repeating every 5 seconds. Smoke alarm pattern is three long beeps with voice "Fire!", and three long beeps repeating..[10 years product life] Smoke and carbon monoxide alarms feature two replaceable AA batteries and an end of life signal that lets you know when you need to change equipment to ensure safety. Longer product life, so that the family safety up to ten years..[Using a simple] Carbon monoxide detectors and smoke alarms use an automatic test function that automatically checks the batteries and sensors every 80 seconds to ensure they are working properly. The mute button makes it easy to turn off alarms in the event of a false alarm. A yellow light warning will alert you when a product malfunctions..[High sensitivity] The upgraded photoelectric and electrochemical sensors significantly improve alarm sensitivity, thus speeding up response time while minimizing false positives. The device can be quickly and easily installed without electrician, making your life easier.