KOSS i 5

Unique electret microphone hanger design allows you to attach to your jacket or computer audio system for hands free communications and storage
Unidirectional microphone for maximum sensitivity and optimized pick up pattern
Microphone Impedance: (Same as load resistance) 2.2k ohms when used with Koss battery bias supply

Frequency Response 50-8,000 Hz
Impedance (Same as load) 2.2k ohms
Weight 0.2 oz
Sensitivity -63±3dB @ 1kHz, re: 1V/1µ bar