Usage Tips:Product description: SUPERIOR ALARM PERFORMANCE: Proven performance for sensitively detecting dangerous Carbon Monoxide (CO) leaks; powerful 85 dB alarm tone will sound through your home and instantly alert those in danger [High Sensitive & Quick Responsive]Build-in smart Carbon Monoxide Detector Chip and the electrochemical sensor, Enough to detect smoke and odorless, invisible and deadly carbon monoxide in the air, Quick reaction to save your life in the first time when fire hazard occurs. [Component Advantage]Human Voice Notification Prompt, High reliable electrochemical sensor, Corbon monoxide concentration displaying (PPM), Low Current consumption, Ultra-long Standy time, Alarm Memory Function, Low Battery Prompt, Auto Detect Sensor Failure. [LCD Digital Display]CO Detector offers Voice Notification and a digital readout of the CO concentration. Detecting level range: 0-999PPM. Alarm concentration: 30-999PPM. It can display both current reading and a reading from memory of the highest level measured over a period of time. [Easy Installation & Widely Used] with screws and anchor plugs, just drill holes in appropriate positions, and done; Used for Each bedroom sleeping area in your home kitchen and living room, and any rooms with an increased risk of fire danger can be installed a smoke detector and carbon monoxide alarm. FEATURES: 1. MCU processing and SMT Manufacture Technology 2. Human voice prompt 3. High reliable electrochemical sensor 4. Carbon monoxide gas concentration displaying(PPM), clock displaying (24-hour system) 5. DC 9V by battery 6. Low current consumption, ultra-long standby time 7. Battery capacity displaying 8. Alarm memory function 9. Auto detect sensor failure Note: 3 x AAA Battery not Included Material: plastic colour: White Package Contents: 1 x 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.