... output power: 100mW +100 mW2. Headphone Adapter Impedance: 16-400Ω3. recommended headphone impedance: 16-64Ω4. harmonic distortion: THD + ... design, cost-effective portable headphone amplifier, perfect sound quality.3.TI, HIFI level by the United States large current professional ... , Germany ERO fever.6.selection of quality high capacity lithium polymer battery(700mA), has a long life with a variety of ...