Koss Pro4AAA Titanium Stereophone High-quality stereophones designed for professional recording and broadcast applications 2 mm mylar diaphragms with titanium coatings deliver unmatched performance Closed, vinyl Pneumalite ear cushions seal tightly around the ear for improved isolation 10 Hz to 25 kHz frequency response; earcups fold flat for convenient travel and storage 8-foot cord, 3.5 mm plug with 6.3 mm adapter included ; includes sleek protective case; no-questions-asked lifetime warranty