Koss QZ-5 Noise Reduction Headphones (Discontinued by Manufacturer) Frequency Response: 40-20,000 Hz Passive noise reduction stereophone system isolates listener from ambient sounds up to 20 dB. Stereophone features neodymium magnet structures for outstanding clarity and definition Ideal for use with racing scanners and metal detectors. Unique head-strap, velcro design allows for a secure fit and immobilization of stereophones (2 straps included) Includes 6.3 mm plug adapter for home use