Infrared Sensor Split Wireless Doorbell Specification: Brand new Receiver size(approx.)?76*80*33mm PIR Sensor size(approx.)?80*59*45mm Weight(approx.)?0.17kg Working Range: Up to 70 meters Infrared sensing distance: 3-7 meters Working Voltage of the Receiver?110V-240V Working Voltage of the PIR Sensor?4.5V?3 AAA batteries? Tips: Do not place the detector in areas where the wind will move it, also try to keep the detective in a clear path to the receiver, so that you can get optimal performance. Care & maintenance portion 1.Important: please keep the detector & receiver in sheltered places to avoid contact of both units form water and direct sunlight. 2.When the LED indicator does not go on , the battery power is either low or dead. At that time you should change the batteries. 3.Clean the detective regularly with a damp cloth to avoid blockage of sensor by dirt or any small particles. 4.Try to keep it in areas where it will not get wet. In addition, during heavy storms & snowfalls, it is recommended that unit should be moved indoor or in a safe place. 5.Never attempt take apart the units. 6.When the unit is not in use, take out all batteries; clean both units and store the units in dry , cool place.