Koss makes sure you can turn up the volume without disturbing the neighbors. The company makes stereo headphones, or "stereophones," and related accessories for consumers and audio professionals. Its lineup includes full-size, noise-cancellation, portable, earbud, and wireless headphones. Products are sold through more than 17,000 US retail outlets, including specialty audio stores, discount stores, and mass merchandisers, as well as by catalogs and online merchants. The company also produces classical music recordings through its Koss Classics subsidiary. In addition to its US operations, Koss has an international sales office in Switzerland. Founded by John Koss, the firm has roots reaching back to the 1950s.