Sennheiser HD 599 Open-Back Around-Ear Headphones 506831 - Matte Ivory, NOB Contents: Headphones, cable, Adapter, Manual, Box. New Opened Box Condition. Description The matte ivory HD 599 Open-Back Around-Ear Headphones from Sennheiser are a successor to the popular HD 500 series and are powered by Sennheisers proprietary transducer technology including the Ergonomic acoustic refinement (E.A.R.) design, which channels the audio signal directly into your ears. They can be used to deliver high-end audio performance and offer exceptional wear