SmartX Battery Powered Wireless Calling Bell / Doorbell set with 1 Receiver/Sounder + 2 Transmitter/Button. Perfect for multiple entrances or rooms. Features 300M long-range coverage (open area), 60 ringtones, 5-level volume (0–110dB), and easy DIY installation. 300 Meters Long Range Receiving Distance in Open Area 60 pcs Ringtones 5 Level Volume: 0-110db Receiver Runs from AA Battery * 3 pcs (included) Transmitter/Bell Button Runs from Battery 23A12V Battery * 1pc (included)