Easy to ask for help for an elderly person, no need to wake up the whole house; just press the button to ask for help Very suitable for patients, elderly, residents, handicapped and pregnant women quickly send alerts to nursing staff The maximum wireless transmission distance is 800-1000 meters Easy to carry, clip it on your collar; hang it on your neck as a pendant; fix it on the bedside and toilet; convenient for the patient; depends on the requirements Meet the needs of all hospitals, clinics, nursing homes, restaurants, hotels Specification: Receiver: Function: display calling function, calling time, calling sequence Power supply: USB interface Alert Mode: Vibrate or Beep Receive sensitivity: -110dbm Frequency: 433.92MHz Storage capacity: 20 groups of real-time call information Transmission distance: 800-1000 meters Battery: 3.7V 230mAh (included) Receiver size: 52.3*61.7*16.5mm SOS Call Button: Battery: 200mAh CR2032 button battery (included) Modulation method: ASK(AM) Launching distance: 200m (open field) Working: -10C to 50C RF frequency: 433.92mh SOS call button size: 55*30*10mm Package included: 1 x Receiver (with Hanging Rope) 5 x Call Buttons (with Hanging Rope) 1 x EU Power Cable 1 x English and Chinese User Manual Other things not included