First Alert PR710A-6 Slim Series Lithium Battery-Powered Photoelectric Smoke Detector White

Low-profile smoke alarm reliably detects smoke from smoldering fires
Slim, easy-to-install design is half as thick as a standard smoke detector
Built-in 10-year battery offers continuous power for the life of the alarm
Photoelectric sensor detects smoke while minimizing false alarms
Patented smoke entry system allows for a direct path to the sensor