Etymotic MicroPro ER-4S Stereo Earphone

ER-4S Stereo earphone have the most accurate frequency response for reproducing CD and MP3 recordings. The sensitivity is comparable to home and professional earphones. ER-4S Stereo earphone are ideal for home stereo use and computer use. ER-4S Stereo earphone can be used with a Earphone amplifier when using low power portable devices. ER-4S is the earphone preferred by musicians and audiophiles.