The 7139 for wall mount is a photoelectric single station smoke alarm designed to give reliable early warning of the presence of smoke where both audible and visual alarms are required. This model is AC powered (plug-in) so an electrician is not required for installation. One year warranty.
The smoke alarm operates on the light scattering principle, a superior method of detection in smoldering fires. It has a pulsing LED light source and a photodiode sensor in a fully screened sensing chamber. When smoke enters the chamber, the infrared beam is deflected onto the sensor. The LED rate increases to 8 times the normal pulse rate, and after the photodiode confirms the presence of smoke for 2 consecutive pulses, it will produce the signal necessary to trip the audible and strobe light alarms.
The 7139 series provides the temporal 3 (T3) evacuation tone as a standard feature. When testing, it may take up to 16 seconds longer to go in or out of alarm.
Features: 177 candela rating (very bright strobe light) Solid state 90dB horn (very loud) Full function test switch (easy for you to test that it is working) Flashes 60 times per minute Meets state, federal, and ADA requirements Temporal 3 (T3) Evacuation sounding device 9V battery backup (audible alarm only) UL Listed (USA)