Unit: 3 Miniature Balanced Armatures Plug Type: 0.78mm double needle Plug iameter: 3.5mm Frequency range: 20Hz-20000Hz Sensitivity: 113dB(±0.05dB) Impedance:28Ω Wire: Sixteen-core high-purity single crystal copper Technical Features: 3 Frequency division,3 Sound hole Craf: 3D printing