The wireless doorbell is an ideal unit to alert the business owner or home owner that someone approaches the door. With wireless plug-in receiver and battery powered motion sensor, it is easy to install and move. The door chime features 52 ringtones and 4 volume levels to suit your needs, and can reach up to 80m barrier-free wireless distance; the sensor can be triggered when detects movement in 5m. Using learning code for pairing, you can add more extra receivers or sensors to expand this alert system to meet your different requirements. Main Features: 1. Stylish modern design fits into any home and office. 2. 52 ringtones(16 chord). 3. 4 steps volume control (25~110dB). 4. Be alerted when motion is activated. 5. 110°x 5m detection zone 6. 80 meters barrier-free of receiving range 7. Simple to use and easy-to-install without any wires. 8. Eye-catching backlight flashes when the PIR motion sensor is triggered 9. Different quantity of transmitter and receiver are free to pair together. 10.Low power alert with red LED light. Product Name Motion Sensor wireless doorbellVoltage of Plug-In Receiver AC 110V ~ AC 220V 50Hz/60Hz Plug type AU,US,EU,UK optional Battery in motion sensor AAA 1.5*2 Wireless Range 350 ft in Open Air; 100~200 ft w/ Metal Security doors and Walls Volume Range 4 Levels (up to 120 dB) Working Frequency433Mhz/315Mhz Working Temperature-20℃~50℃