List Price was $129.99
Features :
ONELINK Enabled Alarm automatically communicates with other ONELINK-enabled alarms when installed
Build a safety network of interconnected alarms in your home without the cost and hassle of wiring
915 MHz, 65,000 security codes and 3 channel frequency hopping provides reliable and secure radio frequency communications between alarms
Connect up to 18 Onelink alarms in your home and when one sounds, they all sound for increased whole-home protection
When programmed, a voice will give you the location and danger sensed by the initiating alarm
Example of voice alarm: “Warning! Evacuate! Smoke in Kitchen!”
Loud 85db alarm
Provides the earliest warning for your family
Battery-Operated Smoke Alarm (4 AA batteries included)
EZ access battery door, no need to remove alarm from ceiling to change battery
Photoelectric smoke sensor reduces nuisance alarms from cooking smoke or shower steam
Test button allows the test of alarm functions and battery, plus silencing unwanted alarms
Compatible with ONELINK carbon monoxide alarm (not included in this sale)
Eco-friendly, completely recyclable as an electronic device
Meets UL217 standard
First Alert One Link Voice Smoke Detector, SA511CN2-3ST-2-Pack : SA511CN2-3ST - Buy.com
First Alert One Link Voice Smoke Detector -2-Pack for $49.99 FS 
