FIRST ALERT 1042253

Onelink smoke and carbon monoxide battery, 2 in 1 protection smoke and carbon monoxide alarm. Photoelectric smoke sensing technology. Electrochemical carbon monoxide sensor. Battery operated quick and easy installation. Voice alerts tells you the type and location of danger. Wireless interconnect when one alarm sounds, they all sound. Emergency notifications notifies you if something is not right in your home (on your phone). 5 year limited warranty.