About This Wide Application: It's an ideal for both caregiver and patient/elderly/resident/handicapped when calling for help at hospital/home. Not need to yell to get someone’s attention. Signal Distance: Using adaptive high-frequency technology, around 100-150M transmission distance in open area, 30-50 meters even with obstacles. Anti-interference, strong penetration and signal stability. Easy to Install: Pager receiver could set in living room, floor corridor, passage, room door, kitchen, nurse station or any other location. Call button can be fixed in bedside/washing room/hospital ward/toilet or any else. The double-sided sticker is included. Practical Cancel Function: The elderly can pull down the red cord or press the SOS key to call quickly, then press the "CANCEL" key to cancel this calling after the older/patient got help. Volume Adjustment: Caregiver pager system can adjust the volume. What's more, you can change the ringtone, prompt time and light color as your needs. Overview Color : K-4L+K-HC-P 2+2 Brand : KOQICALL Power Source : DC Compatible Devices : Receiver, Call Button Battery Description : Alkaline