Review on Enhanced Performance Carbon Monoxide Detector by Kidde with Battery Backup, Digital Display, LED Lights, and CO Alarm by Pete Brown

Bought this unit about a year and a half ago. While it worked for me, it seemed to work fine. However yesterday at 1am a 4 tone alarm sounded. As no other alarms were sounding in the area, I proceeded cautiously by opening all doors/windows and turning on all fans. I then replaced the battery on the device and within 20 minutes the device was back up and running with a 4 tone alarm. Also, the LED displayed a wide range of measurements - all ranging from 30 to 336. Seeing such high numbers was horrible, so I immediately went outside. I also talked about calling the fire department. However, since the other alarms in my house were NOT sounding, it occurred to me that this unit might be faulty. Needless to say I didn't sleep well and left all the windows open and the fans running just as a precaution to make sure I didn't die of carbon dioxide poisoning. In the morning I tested the failed device with a different set of batteries and after about 10 minutes the 4-tone alarm sounded. First, the manual says that the error tone must be completely DIFFERENT from what I've heard that the 4 tone decibel beep is supposedly reserved specifically for the alarm clock. Not the case, a trouble alarm sounded. There was also no visual indicator that the block was bad - no ERROR, no ERROR, no LB message. Nothing like that. Needless to say, I was at Lou's at 7am sharp today to purchase the most expensive replacement I could find after a sleepless night. Plugged in the new alarm clocks and that was it - plugged them in for hours and they never rang. It was an inexpensive product - and it definitely showed. The block is now in the trash and has been replaced with two more expensive ones that connect to a First Alerts battery backup.