KEY SPECIFICATIONS & FEATURE: 1. Working frequency: 433.92MHz 2. Receiver: Lithium battery included; Transmitter: 1*CR2032 1.5V DC 3. Transmitter: waterproof IP44 4. Distance (free field): 152m 5. Volume selection: 16 levels of volume adjustment 6. Music Ringtones: 38 Hexuan Ringtones 7. CE RED security guarantee