Koss QZ2000 Technology Stereophones have a revolutionary Active Noise Reduction (ANR) stereophone system built right in. It reduces harmful and annoying low frequency sounds in noisy environments. This allows concentration without distractions. Open, hear-through ear cushions are designed to rest comfortably on the ear for longer wearing periods and the headband adjusts for a better fit. The compact control case and collapsible stereophone are portable and perfect for travel. The Koss QZ2000 includes a straight, dual entry, four-foot cord and an input jack for audio play-through.