Koss KEB4 Portable Earbud (White) Ultra-Lightweight Earbuds Includes See-Through, Compact, Wind-Up Spool Carrying Case Freq Resp: 70 Hz-20 Khz Imp: 32_ Dynamic stereophone element provides an extended frequency response of 70-20,000Hz Includes convenient wind-up spool carrying case for protective storage L-plug for improved reliability and durability Ultra-lightweight design Straight, dual-entry 4ft cord