Koss 168824 Zipline Earbuds Lightweight In-The-Ear Earbuds Dynamic Element Provides Extended Freq Resp Retractable Mechanism For Convenient Cord Management and Easy Portability Freq Resp: 60 Hz-20 Khz Lightweight in-the-ear earbuds Dynamic element provides extended freq resp Retractable mechanism for convenient cord management & easy portability Freq resp: 60 Hz20 kHz Imp: 16