The TE-01n are Fostex's entry level， high performance inner ear headphones. They are ideally suited for daily use with portable music players or phones， offer excellent sound quality with 4 buds sizes for different ear size. Type: Dynamic Driver: 9mm driver unit with powerful neodymium magnet Impedance: 17 ohm Sensitivity: 110dB/mW Maximum Input: 20 mW Reproduction Frequency: 20Hz - 20kHz Cable: 1.2m Plug: 3.5mm stereo mini plug