Koss KDX300 Gold Noise Isolation Earbud Stereophone - (GOLD) (Discontinued by Manufacturer) Lightweight With In-The-Ear Design That Delivers Accurate Acoustical Reproduction, Deep Bass and Isolation Typically Found In Closed-Style Stereophones Features A Dynamic Element That Is Positioned Just Outside The Ear For Extended Freq Resp Freq Resp: 10 Hz-20 Khz Imp: 16