Smoke detector GS522 stand-alone

Smoke detector GS522, photoelectric smoke detector (not radio networked)
The GS522 is a photoelectric smoke alarm; it also responds sensitively and reliably to slow, smoldering fires, which generally produce thick, black smoke at low heat before developing into open flames.
The red LED flashes once every 40 seconds to indicate operational readiness. After 10 years, when the battery becomes low, a periodic beep will sound, which can be disabled by the mute button for 10 hours.
At least 1 smoke detector should be installed in every room of the house (except the kitchen/bathroom).