CO Detector Smoke and Carbon Monoxide Detector Combo with Sound Warning and LCD Display Battery Operated Smoke CO Alarm

This CO and smoke detector uses an electrochemical carbon monoxide sensor--the most accurate CO sensor available. Compared with the more commonly used techniques, electrochemical technology, electrochemical technology is highly accurate, requires a lower amount of power, and boasts a longer life. ?Specifications?  - LCD display concentration PPM - 3*1.5V AA battery ( package not include) - Ultra-long standby time, low current consumption - Low-battery warning - Alarm memory function - pause(Hush Mode) - Sound & Flash Alarm & LED indicating Alarm - Temperature: 0?-50? - Relative Humidity: 10-95% - Alarm indication: LCD display, Light/sound prompt  - Dimensions: ?4.09*1.53in - Item Weight 0.4 lb ?Battery Operated for Convenience? After installing batteries, you can hear a sound of "di", and it starts working normally after about 2 minutes. In operation, the LCD display nothing (power saving design), the green LED lamp flashes every 35 seconds. ?About Installation? 1.Need to be installed in living rooms, ceilings, cars or other places where people stay for long periods of time. A better option is to install it in the bedroom, hallway, basement, car or living room. 2.When installing the alarm, do not place the product near the fire source. Do not install it in the bathroom or in any other place with vapor mist. In addition, do not install it in a place with a lot of smoke to prevent clogging of the machine and will not have any effect on the alarm sensor. 3.The concentration of carbon monoxide and smoke is smaller than that of air. So,please install the sirens at 0.3~1m below the ceiling. ?NOTE? This detector is easy to be effected by the sharp pounding and shock in transit or installation,lead to not work.Please note that when you receive the package, press the "TEST" button to check if the device is working properly.