The Pathfinder features a dynamic element that is positioned just outside the ear and connected to a tubular port structure that is inserted on a soft expandable cushion into the ear canal. The soft foam cushion expands for a custom fit to improve isolation and enhance deep bass and treble clarity. Now with improved slow memory ear cushion made of hydrophilic, formed urethane, you are guaranteed a custom fit every time. The Pathfinder also features a white cord to compliment many mp3 players. The fit enhances isolation when you want to plug out ambient sounds that interfere with the listening experience. The Pathfinder has a frequency response performance of 10Hz-20,000Hz and full Sound of Koss. Combined with your favourite music and a portable sound system, it is the ultimate accessory on the go.