Noise cancelling headset: JH-304B features:

1. Active noise cancelling technology to enhance the power of noise filtering.
2. Block the external noise to offer a superb listening experience.
3. Headphone foldable and cable detachable design, convenient for traveling users especially for users in noisy environment like subway, airline, highway, etc.
4. Noise cancelling and common wired headphone available
5. Driver unit: 40mm dynamic speakers
6. Impedance : 32Ω±10%
7. Frequency response : 20Hz - 20KHz
8. Reduction level: >18dB at 300Hz
9. Sensitivity: 102 dBμv at 300Hz
10. Cord length: 1. 2m
11. Plug: 3. 5mm stereo plug
12. Power requirement: 2 × AAA batteries(not included)