【Combination Gas & Carbon Monoxide Detector】2-in-1 sensor design, high sensitivity, high reliability and high accuracy. 【Plug & Play Design】Easy to install, easy to read, saves installation time. 【85DB Alarm】 - When carbon monoxide gas is detected at the default value, the carbon monoxide detector will quickly alarm you to make the first choice. 【2-in-1 Real-time Display Gas Concentration】When the dangerous gas is detected, the device reacts immediately so that you can see it at a glance. 【Application】gas & carbon monoxide detector is suitable for home, apartment, kitchen, bedroom, bathroom, RV and etc. 2 Packs Combination Gas & Carbon Monoxide Detector, Plug in Carbon Monoxide Alarm & Natural Gas Detector,Propane,Methane,with Backup 9V Battery Feature, Digital Display, for Home, Apartment, RV