Mengshen Entry Door Bell Alarm Chime Doorbell Wireless IR Infrared Monitor Sensor Detector Split Alarm MS-YBQ03 Wireless door chime is suitable for retail store, shop, business, salon, front / back / side door, etc. Attach this infrared alarm anywhere you want and instantly know when someone crosses the beam. Infrared sensor detects motion and sends a signal to the receiver. The chime is loud and clear. It is energy saving and multifunctional, used as welcome entry bell and doorbell. Working Range: Up to 100 meters (open field)