Specifications: Output power: ? 1100mW (32 ohm) Adapter Headphone Impedance: 18-600 ohm Total harmonic distortion: <0.005% SNR: ? 110DB Frequency Response: 20-30KHz Size: 111 * 69 * 32 mm (L * W * H) ， (height 73mm when add tube) Net Weight: 185g Package include: 1PC headphone amp 2PC 6J9 tube 1PC power supply (Not include audio cable， please note!)