Sennheiser HD 559 Open-Back Around-Ear Headphones Black 506828, NOB Contents: Headphones, Cable, Manual, Box. New Opened Box Condition. Description The black HD 559 Open-Back Around-Ear Headphones from Sennheiser are the successor to the popular HD 500 series. They are an ideal choice for listeners seeking an optimal blend of all-around performance and quality for home entertainment. Featuring Sennheisers proprietary transducer technology, these headphones have an Ergonomic Acoustic Refinement (E.A.R.) design, which channels the audio signal