1、Designed with the principle of light controlled induction, it can be used as a convenience store for visitors to inform and open at night, with a detection range of about 3‑7 meters. 2、One machine is multi purpose, the receiver has ultrasonic mosquito repellent function, adopts fashionable streamline design and sandblasting high grade craftsmanship with multi color optional decorative strips. 3、It is recommended to use it under the condition of sufficient light. If the ambient light is insufficient, the detection distance will change from far to near. This is normal. When the music becomes weak, please replace the battery (Not Included) in time. 4、It is easy to be safe, completely free of decoration expenses, no need to gouge the wall, it can be used by plugging in a regular indoor socket, and the installation position can be moved at will. 5、Using wireless high frequency transmission technology, innovative same frequency different code and dialing functions, the error rate is only one in 200,000, effectively avoiding the troubles caused by mutual interference and false noise between neighbors. Item Type: Doorbell Material:ABS Weight: Approx. 116g / 4.1oz Product Size: Approx. 8x8x4.5cm / 3.1x3.1x1.8in Battery Parameters: 3xAAA R03P (not included) Detection Range: 3-7m/9.8-23ft Current In Standby: ≤0.1mA Working Voltage DC: 1.5V A variety of music can provide options: A. Dingdong, hello! welcome B.Ding Dong,Hello,Welcome C.Ding Dong, Salam Walaikum D.32 music circulation 1 x Welcome Doorbell (Battery Not included) 1 x Accessories 2 x Screw