Wrist r Receiver need to be paired with the calltou transmitter then the unit can work well together. Wrist r Receiver can work with the SOS Call on as a caregiver r/call system for Both Caregiver and Patient/Elderly/Resident/Handicapped/Sick Freedom while Still calling for Help at home. Not need to Yell to Get Someone’s Attention.SMART CAREOGIVER ALERT: Vibration or Audible Prompt for choice. Wake Up the Night Shift Caregiver Only, And not wakeup/disturb the others. Wrist r Receive is powered by Built-in Rechargeable battery. Standby time about 3 days.Please search B077YF5ZWS/B07FXR9ZXS/B07FL9T4BY/B07GTFCS6W/B07M65TL51/B07KXQL9WY/B075VM7TYD/B078BQKT23/B077SYPD5K/B077VMC89R/B07H29R7JD/B07FTW33ST/B07JM47GLM/B07C1H4J5D/B073S62TK1 to puchase calltou call ons and other calltou receivers.