Wireless Smoke Detector,Ceiling mounted
RF distance: 150m ( line of sight )

  Wireless Smoke Detector SD-305W

Ceiling-mounted
RF distance: 150m ( line of sight )
Radio frequency: 433.92MHz±75KHz Op
Standby current:  ≤10μA
Low voltage alert
Self-checking
Dry battery:  9V / 200mAh
Operating temperature: -10°C ~ +50°C