Specifications: Input: 5 volts = 330 milliamps Battery capacity: 35 milliamp hours Working time: 6 hours (maximum) Charging number: 3 Longest working time: 24 hours (maximum) Battery type: Lithium polymer Player type: Ф13mm dynamic driver Frequency response: 20 Hz - 20 kHz Impedance: 32 ohms Sensitivity: 122dB ± 3dB (at 1KHz / -10dBFS) Wireless version: V5.3 Size (earphone) | Weight (earphone + case): 39 × 16.3 × 18 mm | 49 grams ± 5 grams