Product Description:- AC-style doorbell one for two.- Used launching a 12V 23A alkaline small batteries used by the receiver 220V power supply.- 38 Visitors ringtones， 3rd volume adjustment- 50 m Accessible distance wireless receiver is suitable for large suites and villas.- Power By: 12V 23A alkaline battery (Excluding) Installation Method:1. Use a flat open emitter open the back cover， fitted with a small battery 12V2. Tear double-sided adhesive， the launcher standing on the wall， or with screws.3. The receiver can plug in.4. Remote control power: <10mw.5. Receive Rated voltage: AC 220V 50Hz / 60Hz6. The receiver controllable volume: 25-75dB7. Receiver Standby current: <1.0mA8. Receiver plug socket: 220v9. Operating frequency: 315MHz ± 2MHzPackage List:1* Transmitter2* Receiver