Koss MV1 Professional Studio Stereophone High-quality stereophones designed for professional recording and broadcast applications 2 mm high-polymer diaphragms with titanium coatings deliver unmatched performance Closed cushions seal tightly around the ear to minimize ambient sound and improve bass 10 Hz to 25 kHz frequency response; earcups fold flat for convenient travel and storage 8-foot cord; includes sleek protective case; no-questions-asked lifetime warranty