Unit: Sonion 38AM007 (composite low frequency) + Sonion 2389 + Sonion E50DT (composite high frequency) Plug type: 0.78mm twin pin Plug diameter: 3.5mm Frequency range: 20Hz-20000Hz Sensitivity: 115dB (±0.05dB) Impedance: 41Ω Wire: 16-core gold, silver and palladium alloy wire Technical features: 3-way, 3-hole Craftsmanship: stable wood chamber