Technical specifications: USB digital audio input : Support for Apple devices: iPhone5S/5C/5, iPhone4S / 4, iPhone 3G/3GS, iPad (4/3/2/1 generation), iPad mini, iPod touch D / A converter chip: WM8741 Sampling frequency: 44.1/48kHz 16bit Analog audio input ¡ œ 1000mV Headphone output Maximum output power: 130mW +130 mW (32 ohm load) Frequency response: 20Hz-20kHz (+- 1dB) (AUDIO IN analog input) Total harmonic distortion: ¡ œ 0.05% (1kHz) SNR: ¡ 98dB (A-weighted) Lithium battery capacity: 2500mAh Charging time: ¡ œ 4 hours (need power off) Life time: ¡ 8 hours (32ohm load) Charge limit voltage: 4.2V Size: 60mm x 20mm x 130mm (width / height / length)