Description: 【Infrared Motion Sensing】Imported infrared probe, 360 degrees universal rotation, 120 degrees sensing area, sensing distance 3-7 meters. Infrared Sensing detects motion and sends a signal to the receiver. 【 Plug In Receiver】The portable plug in receiver plug into any standard outlet. The working range between the receiver and the Sensing is up to 200 meters (tested in an open field), and you can place it at a suitable distance from the receiver. 【Features】High fidelity speakers are used, and 38 high quality sound effects are built in with low power consumption. Blue LED indicator. 4 level volume adjustment with silent mode. 【Simple, Fast, Installation】Doorbell great for front doors, window frames, driveways, sidewalks, and anywhere in your home where you would like to receive motion alerts. Warns you of the arrival and departure of family members, unexpected guests, or anyone visiting your home or business. 【Package Include】2 plug in receiver and 1 motion Sensing. Receiver size: 8cmx8cm/3.15inchx3.15inch, Sensing Size: 8cmx8.5cmx5.5cm/3.15inchx3.35inchx2.17inch. Specification: Plug: US Package Includes: 1 sensor 2 receivers Note: Please allow slightly errors due to manual measurement and different monitors.