Easily install the First Alert SMCO200 Battery-Operated Combination Smoke & Carbon Monoxide Alarm with Slim Profile Design. The alarm is half the depth of a standard alarm and provides reliable 2-in-1 smoke and carbon monoxide protection. Meets new industry standards with First Alert's Precision Detection advanced sensing technology. First Alert's Precision Detection advanced sensing technology complies with new industry standards to reduce cooking nuisance alarms and provides early warning in the event of a home fire emergency.