The closed Pneumalite ear cushions and extra-secure headband create a tight seal around the ear eliminating all ambient noise and are built to withstand the rigors of indoor and outdoor use. QZ99 are not only for noise isolation, but also for sound quality. The QZ99 Passive Noise Reduction headphones sport neodymium magnet structures that deliver outstanding clarity and definition. The Koss QZ99 also includes a volume control on the ear cup that makes adjusting sound levels a snap, and a stereo/mono switch that extends user flexibility. Sporty and strong with superior sound quality, these Passive Noise Reduction headphones are every audiophile’s dream.