Review on 🚨 X-Sense CD07 Carbon Monoxide Detector Alarm with 10-Year Battery, LCD Display, UL 2034 Compliant by Michael Montgomery

I installed this device according to the instructions, tested it and assumed I would now be notified if there was a problem with CO at my home. Three months after the installation, I was woken up at 2am by the fire department. The apartments above and below me called 911 because they had a CO detector and I didn't. The fire brigade checked their apartment and mine (right next to the X-Sense detector), found that the carbon monoxide levels in the air were too high, and evacuated us. The X-Sense alarm showed "0ppm" for the 2 hours this process lasted. I have notified X-Sense that I believe I have a defective device. They replied that the device's display does not actually show the current PPM concentration and does not beep unless it is at least 70 ppm for 60-240 minutes. This PPM is above what firefighters and gas companies have identified as a safe level. If I relied on this alarm clock, I would sleep while my house fills with CO.