Earphone Driver unit: 10mm diameter Cobalt Impedance: 32 Ohm ± 15% Sensitivity: 125dB at 1KHz Microphone Type: 6mm diameter electret condenser Directivity: omnidirectional Sensitivity: 158dB ± 2dB Impedance: U=4.5V, R=2.2KOhm Frequency response: 30-16,000Hz