Kidde Intelligent Alarm Battery Operated Combination Smoke & Carbon Monoxide Alarm KN-COSM-XTR-BA Voice Alarm - Announces the hazard type detected thereby helping to speed up the correct reaction to the hazard detected. Alarm announces Fire Fire when a smoke or fire hazard is detected and announces Warning Carbon Monoxide when a CO hazard is detected. The Hush feature temporarily silences nuisance alarms. Combined Carbon Monoxide and Smoke Alarm - A single unit can be installed where previously, two were needed. Reduces installation time and helps to keep home dcor attractive. Test/Reset Button-Tests alarm circuitry and triggers the voice announcement. LEDs - Flashing green for normal operation and flashing red for alarm condition Low Battery Warning - The unit warns of a low battery condition by announcing low battery and by initiating an alarm chirp and activating a flashing red LED. Provides protection even during power outages when many fire and carbon monoxide incidents occur. The battery door will not close unless the batteries are properly installed.