1. Double noise reduction, no need to adjust
2. Charge for 2 hours, battery life is 30 hours
3. Type: In-Ear
4. Power supply: rechargeable
5. Working voltage: 3.7V
6. Rated operating current: less than or equal to 1.4mA
7. Frequency response: should not be narrower than 300-5000
8. Maximum saturated sound output: less than or equal to 128+/-3 decibels
9. High frequency average: 106dB +/- 4dB
10. Gain: 28db+/-5db
11. Total harmonic distortion: less than or equal to 7%+3%
12. Equivalent input noise: less than or equal to 29+3db
13. Dimensions: diameter 42 x 31mm
14. Net weight: 4.3g