More than 60 years of ingenious headphone engineering has been applied to the new HD 800. Incorporating Sennheiser's most advanced driver technology, these open, around-the-ear, dynamic stereo headphones redefine what reference-grade audio is all about. The HD 800 is hand-assembled in Germany with only the finest of materials. The transducer is encased in a precision material made of stainless steel, while the headband and headphone mounting utilizes the most advanced development from the aerospace industry.