2 units in 1: unit alerts you to smoke & carbon monoxide by sounding a loud, 85-decibel alarm & sounding voice alertsPhotoelectric sensor technology senses visible fire particles, while a electrochemical sensor detects CO gasVoice Alarm & an 85-decibel alarm announces a hazard when detected: “Fire!” = smoke or fire or “Warning Carbon Monoxide” = CO gas, or "Replace Alarm" when the alarm has reached its end of life spanOperates on a 10-year lithium battery, eliminating the need for battery replacement, while providing reliable detection during a power failureCombination fire alarm automatically activates when it is attached to the mounting bracketTest-Hush Button makes testing the detector or silencing false alarms easy (false alarms may occur from routine cooking, shower steam, dust or humidity)UL listed with a 10-Year limited manufacturer warranty on the alarm only (not a battery performance claim). Warranty begins when the alarm is powered on. If that date is unknown, it should be assumed that replacement is needed.
