CACAZI A10 300m Long Range No Battery Waterproof LED Light Smart Wireless Doorbell 1. This AC doorbell receiver (indoor unit) uses household power and can be plugged directly into an outlet, eliminating the need for batteries. It's environmentally friendly and convenient! The transmitter (outdoor unit) is powered by a single battery and lasts approximately one year. 2. Superior reception with an unobstructed, straight-line transmission range of up to 300 meters. Suitable for homes, offices, hotels, restaurants, dormitories, factories, and more. 3. Utilizing wireless high-frequency transmission technology with the same frequency and different codes, it effectively avoids interference and false ringing between neighbors. 4. Three adjustable volume levels and 38 music tracks available. 5. Built-in LED indicator that flashes when the doorbell rings. 6. The transmitter meets IP44 waterproof standards, effectively preventing rain intrusion and extending its service life. 7. Operating frequency: 433MHz. 8. Power supply: The receiver supports direct plug-in AC 100V-240V. The transmitter uses one 12V 3A battery (not included). 9. Dimensions: Transmitter 75x51x20mm, Receiver 95x65x24mm