About this item 2-pack 4in1 CO & Gas detectors This newest combination 4in1 CO&Gas detectors Integrated carbon monoxide, combustible gas, temperature and humidity sensors, real time to detect the environment gas safety for us. Gas detecting type: carbon monoixde natural gas, propane, methane, natural gas, coal gas, gasoline, Hexane, butane, benzene, ethyene oxide, acetylene, LPG, LNG, etc. Plug in&Play design US standard plug is compatible with 110V to 220V AC outlet. Fits all US standard AC outlet in bedroom, kitchen, living-room, basement, hotel room, office etc. 2.1’’ HD Screen play design All the data real times shows on the HD screen, we can read the data faster from the big icons like: CO ppm, combustible gas indicating bar, humidity, temperature, CO indicator icon, and alarm status. Also we can judge the brightness status from brightness icon. All gas environment safety we care Built-in UL1484&UL2034 standard independent combustible gas sensor and CO sensor, HD screen visible and 85 dB audible design is real time detect the gas environment, bring you extra safety for your and family. To create a full house safety warning for you.