First Alert SA521CN-3ST Hardwired Onelink Wireless Smoke Alarm

<p>The First Alert SA521CN-3ST Interconnected Smoke Alarm allows owners to create an interconnected fire alarm system without the cost and hassle of wiring. Use this smoke detector to replace an existing hardwired smoke alarm and then install additional First Alert Wireless alarms for an interconnected safety network. This hardwired smoke detector can connect and communicate with up to 18 compatible alarms, so when one alarm is triggered, the entire system reacts. An integrated battery backup ensures the smoke alarm continues to work even during power outages.</p>

• 120V AC hardwired, easily replace one existing hardwired alarm with First Alert SA521 alarm and then add Wireless Interconnect battery operated alarms to connect wireless alarms with hardwired alarms when one sounds, they all sound
• Battery backup provides consistent protection for added safety during power outages
• Photoelectric smoke sensing provides optimal protection from smoldering fires, while reducing false alarms like those caused by cooking fires and shower steam
• Mute button silences unnecessary alarms immediately. It also tests alarm function with same button
• Eco-friendly, completely recyclable as an electronic device
• EZ access battery door, no need to remove alarm from ceiling to change battery
• 2AA batteries included
• Loud 85 dB alarm; meets UL217 standard