[. . . ] [. . . ] Parameter Working Volt: DC 3V2xAAA batteries Working Current:<55mA (0. 7 sine wave loading volt) Noise Reduction: >16dB at F=300Hz BTS-100 Noise Cancelling Headphone adopt special electrical circuit to reduce the surrounding noise, which can improve hearing effect. Sensitivity: 114dB ±2 dB at F=1KHz Frequency Response:20Hz~20KHz HP- 080 1. Features This item is suitable for any audio devices. Try to avoid touching this item with sharp object in order not to influence the appearance. [. . . ] [. . . ]