KN-COSM-XTR-B Nighthawk Combination Carbon Monoxide, Fire, and Smoke Intelligent Alarm (4 Pack)Product ReviewP Click on the link for more reviewsPVoice alarm, announces hazard type detected helping to speed up correct reaction to hazard detectedPCombined carbon monoxide and smoke alarm, single unit can be installed instead of two, reducing installation timePTest reset button tests alarm circuitry and triggers voice announcement, flashing green and flashing red LEDsPLow battery condition announcement initiates alarm chirp and flashing red LED activationPBattery powered, provides protection even during power outagesP