Fangrui Product Details 1. 1 To 2 Pir Infrared Sensors Wireless Doorbell Alarm Detector For Home Office 2. Features 3. Adopt Advanced Infrared Detect Technology. 4. No Wiring Design Makes It Simple To Use And Easy To Install. 5. Up To 100m Wireless Working Distance In Open Area, 10m For Indoor Use. 6. Wireless Installation, Just Place The Sensor At The Entrance. 7. The Receiver Volume Is Adjustable 8. The Receiver Will Send Chime Sound And Illuminate Red Led Lights When The Pir Devices Detect Somebody Is Near. 9. Sensor Transmitter With Installation Brackets, Convenient To Adjust Detect Angles As Need. 10. It Is For Home, Office, Or Commercial Buildings. 11. 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). 12. Support 1 Receiver And 2 Transmitters Work As One Group. 13. How To Use 14. Open The Sensor Cover, Install 1 X 9v Battery, Then Opens The Switch In Circuit Board 15. Open The Receiver Cover And You Can Install 2 X Aa Batteries 16. Push The Switch On The Side Of Receiver To Open The Switch 17. Install The Sensor On The Both Of Door Side Or Other Some Places You Want To Detect Human Body Passed By 18. Adjust The Receiver Tone Volume, The Power Switch To The Mid-position Is Low-volume, High-volume On Uppermost Position 19. 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 20. 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. 21. Note 22. Do Not Place The Detector In Areas Where The Wind Will Move It; Also, Try To Keep The Detector In A Clear Path To The Receiver, So That You Can Get Optimal Performance.