Consumer Reports’ lab tests reveal a performance problem with the USI Electric MPC122S smoke, fire, and carbon monoxide alarm.

The RSA-400 is reasonably priced. A similar USI smoke and CO detector costs $50, plus the $35 Roost. The RSA-200 is less so, as a USI detector that just smells smoke is only $12.

Consumer Reports shares details of Universal Security Instruments' recall of the MPC322S and MPC122S smoke and CO detectors due to their failure to alarm at dangerous carbon monoxide levels.