Specifications: 

1. Microphone: Wireless microphone

2. Input voltage: 5V

3. Microphone battery: 110mAh (2 pcs is 220mAh)

4. Charging compartment battery: 800mAh

5. Battery life: 9 hours

6. Signal-to-noise ratio: 64DBM

7. Transmission delay: 30MS

8. Sensitivity: -42 dB

9. Frequency response range: 20-20KHZ

10. Transmission distance: 20-30m (barrier-free)