First Alert SA521CN Interconnected Hardwire Wireless Smoke Alarm with Battery Backup

Product Description For those who want a comprehensive detection system without hiring an electrician or worrying about hardwiring, the First Alert SA521CN Wireless Interconnected Hardwired Photoelectric Smoke Alarm is an ideal solution. Use this smoke detector to replace an existing hardwired smoke alarm and then install additional compatible First Alert Wireless alarms for an interconnected safety network (additional alarms sold separately). Wireless technology makes it possible for the detector to connect with up to 18 compatible First Alert wireless-enabled alarms to create a wireless safety network. These connected alarms can communicate with each other and sound in unison. The photoelectric smoke sensor is designed to reduce false alarms from cooking smoke or shower steam while remaining sensitive to real danger. The smoke detector has an integrated battery backup in case of power outages and features a single button to silence false alarms and test the unit. Amazon.com 'The First Alert SA521CN-3ST (Model SA520B) Wireless Interconnect Integrated Smoke Alarm links the alarms throughout your home. This 120VAC hardwired wireless detector with battery backup integrates single alarms into a system. By adding Wireless Interconnect battery powered alarms elsewhere, when one alarm sounds, all alarms will be notified. Easily link alarms with the press of a button. The RF Interconnect technology continues to provide a reliable and secure radio frequency communication between Wireless Interconnect alarms. This technology features 915 MHz frequency with 65,000 security codes, and three (3) channel frequency hopping. The unit is compatible with an assortment of First Alert wireless alarms, which includes the SA501CN-3ST (SA501B), SA501CN2-3ST (SA501B2), SA511B, SA511CN2-3ST, SA520B, SA521CN-3ST, CO511B. SCO501CN-3ST (SCO500B), SCO501CN2-3ST. Photoelectric smoke sensor reduces nuisance alarms. Easy access battery drawer: no need to remove an alarm from the ceiling to change battery. Includes 10-year limited warranty. Meets UL standards. Note: This product is intended for non-professional do it yourself installation. If you would like information about a professionally installed and monitored system, please contact First Alert Professional at 1-800-921-6025. First Alert Professional is not affiliated with BRK Brands, Inc. '