2 to 1 PIR Infrared Sensors Wireless Doorbell Alarm Detector for Home Office Features 1. Brand new and high quality. 2. Adopt advanced infrared detect technology. 3. No wiring design makes it simple to use and easy to install. 4. Up to 100m Wireless working distance in open area, 10m for indoor use. 5. Wireless installation, just place the sensor at the entrance. 6. The receiver volume is adjustable 7. The Receiver will Send chime sound and illuminate red LED lights when the PIR devices detect somebody is near. 8. Sensor transmitter with installation brackets, convenient to adjust detect angles as need. 9. It is perfect for home, office, or commercial buildings. 10. The receiver is powered by 2 x AA batteries (not included) and the PIR Sensor is powered by DC 9V (1 x 6F22, not included). 11. Support 2 Receivers and 1 Transmitter work as one group. How to use 1. Open the sensor cover, install 1 x 9V battery, then opens the switch in circuit board 2. Open the receiver cover and you can install 2 x AA batteries 3. Push the switch on the side of receiver to open the switch 4. Install the sensor on the both of door side or other some places you want to detect human body passed by 5. Adjust the receiver tone volume, the power switch to the mid-position is low-volume, high-volume on uppermost position 6. Adjust the angle of the sensor to a suitable position, when the guest enters its detection range, the receiver automatically sends sweet music ringtones, the red LED lights 7. When you open the sensor power, wireless doorbell is required for each SELF-TEST function, about 10 seconds, and then enter the normal working condition.