THE QZ50 active noise reduction stereo headphone from Koss creates an invisible shield between the listener and droning sounds by stopping low-frequency noise before it reaches the ears. Tiny microphones embedded in the ear cups send incoming low-frequency noise to a tiny processor, which generates a signal that is 180∞ out of phase with the outside low frequency. The two waves counteract each other, resulting in a reduction of the low-frequency repetitive noise.

The QZ50 features a behind-the-head headband design for comfort. Ear cushions provide additional sound isolation.

The QZ50, which operates about 200 hrs. with a single AAA battery, has a suggested retail price of $49.99. Contact Koss Corp., Dept. FIN, 4129 N. Port Washington Ave., Milwaukee, WI 53212, 800/871-5677, visit or, or circle 193.