【The transmitter does not require batteries.】 If you press the transmitter, it generates electricity itself.Therefore, no batteries are required.You no longer have to worry about battery replacement.You can also save around 5 euros per year.When the receiver rings and the blue LED flashes to visually alert you (good for hearing impaired people) 【IP55 Waterproof】The remote control button is IP55 rated, providing safety and waterproof performance.The doorbell can withstand bad weather such as storms, direct sunlight and frost and can be installed anywhere indoors, in the door frame or outdoors. 【Long Range】The doorbell can reach a maximum outdoor range of 200m (656ft).The doorbell's digital circuit design effectively prevents mutual interference problems between neighbors, even when multiple devices are used without crosstalk.Additionally, the device can also be used as a care aid for the elderly or patients. 【5 types of volume and 60 types of ringtones】 Offer different melodies such as chords, jazz, folk music, etc.The volume can be adjusted from 0 dB to 110 dB.You can set different ringtones for each receiver of each transmitter. 【Easy Installation】The knob can be attached to the door frame with screws or double-sided tape.The receiver is connected directly to the power source that needs to hear the sound.It can be used in homes, villas, offices or commercial places.If you have any questions, please contact us immediately.