Audio input: 3.5mm headphone port Headphone output: 3.5mm headphone port Charging port: Type-C Volume adjustment mode: High precision volume knob Power supply: DC 5V 1A Internal voltage：±9.5V Op amp: OPA1642 Current amp: 1W triode to tube Battery capacity: 2200mAH Battery Life: about 12h Magnification (Av): GAIN=L:3 GAIN=H:6.8 Low-frequency gain（BASS=ON）: +6dB Frequency response: 10Hz-25KHz SNR: ＞100dB THD+N: 0.005% Headphone output impedance: 16ohm-600ohm Headphone output power: 16ohm/330mW 32ohm/320mW 64ohm/298mW 300ohm/100mW Dimensions: 4.17 x 2.64 x 0.55 inches (106x67x14mm) Product weight: 126g