our dual sensor smoke alarm is independent Photoelectric smoke & heat alarm, main feature：
1.9v Battery operated for this (SR-820DHS) stand alone smoke detector
2.Infraed Photoelectric sensing technology
3.Lower battery indication
4.Loud 85dB audio alarm
5.Instant test button
6.MCU processing
6.Test and hush button
7.57ºC(135ºF)fixed temperature alarm
8.High temperature alarm
Immediately report to the police when temperature more than 57 degrees
More details：/dual-sensor-smoke-alarm.html
