The Koss CC_01 isolating in-ear monitor-first stereophone to create a perfect fit with unique Custom Fit dial. Rotate knurledknob-ear cushion expands to provide a custom fit. Designed to produce a perfect seal-variable matched transducer couples w/the eardrum for greater accuracy/efficiency across entire frequency response range. New state of the art in ergonomic and acoustic design. Transducer is specially crossmatched for balance across entire musical spectrum resulting in an up-front, exacting performance w/instruments retaining their size and scale on the musical landscape. Specially padded cloth covered cord serves as a wrap around protable digital music players and comes with both a soft leather carrying case and a hard travel case.