First Alert SA521CN Interconnected Hardwire Wireless Smoke Alarm with Battery Backup
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<b>[Product Information]</b><br>
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<li>RF Interconnect offers a reliable and secure radio communication between alarms</li>
<li>One alarm sounds, they all sound to provide earliest warning of potential danger</li>
<li>Photoelectric smoke sensing alarm with mute button</li>
<li>Loud, 85dB audible alarm</li>
<li>120V AC power with 2-AA battery backup</li>
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