HIGH QUALITY CARBON MONOXIDE DETECTOR - The portable carbon monoxide detector is made of high-strength ABS material, which is sturdy and . High-precision electrochemical sensor can more quickly and accurately monitor the CO concentration in the surrounding environment. EASY TO USE - Travel carbon monoxide detector Install the battery, long press the power button to turn on the handheld CO monitor and wait 28 seconds to . You can press the "Hi" button to adjust the screen brightness, and press the "Lo" button to turn on or turn off the alarm. LCD DISPLAY AND AUDIO ALARM - The 1.1Inch LCD screen displays the real-time CO concentration from 0 to 999 ppm, buzzer status and battery level. When the CO concentration exceeds the specified level (50 ppm), the entire screen will turn red and a loud audible alarm will sound. When the battery voltage falls lower than the working voltage, the device will sound an audible alarm of "di-di-di" every minute. After the fifth alarm, the device will automatically turn off. BATTERY POWERED AND POWER SAVING MODE - This pen-type carbon monoxide meter is powered by 2 x 1.5V AAA batteries (not includes). In order to save battery life, the carbon monoxide alarm detector will automatically turn off the screen backlight and enter power saving mode after about 1min of no operation. NOTE: In power saving mode, the gas sensor continues working and monitoring the carbon monoxide concentration. You can press any button to light up the screen again. Colour:White Material:Plastic Package Contents: 1 x HD07 Battery Operated carbon monoxide detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.