Battery-powered  door bell
38 melodies DIY Name Plate Suitable for Home Office                                       
1. Operation frequency：433.92MHz
2. Receiver：3*AA 1.5V DC excluded
Transmitter：1*CR2032 3V DC included 
3. Number of tones：38
4. Transmitter：waterproof IP44                                    
5. Distance (free-field)：150m
6. Volume Selection：yes
7. Permissible ambient temperature：0–35 °C