First Alert CO605 Plug-in Carbon Monoxide Alarm vs First Alert SM210 / SM210V / SM210L 10-Year Smoke

Side-by-side specs from each maker.

Only the differences are shown.

First Alert CO605 Plug-in Carbon Monoxide AlarmFirst Alert SM210 / SM210V / SM210L 10-Year Smoke
TypeSmoke or CO alarmSmoke or CO alarm
AlarmCOsmoke
Sensorelectrochemicalphotoelectric
PowerPlug-in with battery backup10-year battery (lithium metal, not replaceable)
Standards (maker)Not listedConforms to UL 217 10th Edition Standard
Replace afterNot listed10 years

First Alert CO605 Plug-in Carbon Monoxide Alarm

A plug-in carbon monoxide alarm with an electrochemical sensor, battery backup for power outages and a single test and silence button.

  • Battery backup
  • Plugs into a standard outlet
  • 85 decibel alarm
  • Needs an outlet

First Alert SM210 / SM210V / SM210L 10-Year Smoke

A photoelectric smoke alarm with a sealed 10-year lithium battery and a slim profile. Voice and path-light versions are separate models from the same maker.

  • Sealed 10-year battery
  • UL 217 10th edition
  • The maker lists a lifespan of about 10 years
  • Smoke only, no CO sensing