Feel Safe with this Carbon Monoxide Alarm

It was easy to hang the Firstbuy Carbon Monoxide Alarm on the wall upstairs in my house in the hall between 2 bedrooms. If the alarm detects carbon monoxide an alarm goes off and a red LED light flashes. When it says Err on the LED it means the alarm isn't working--Lb means low battery--999ppm  means that the carbon monoxide level is above 999ppm. I inserted 3 AAA batteries and tested the alarm and it worked.I recommend the Firstbuy Carbon Monoxide Alarm. #RankBoosterReview ii, Sponsored iii #Firstbuy CarbonMonoxide Alarm  https://www.amazon.com/gp/product/B074T8DVTF/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1