Up for sale is used excellent condition Sennheiser HD 800 S Reference Headphone System, deliver sound that is as natural as possible and true in every detail. Open back, around ear, reference class dynamic headphone. 56mm ring radiator transducers are the largest drivers ever used in dynamic headphones. Innovative absorber technology reduces unwanted frequency response peaks allowing all the music nuances to become audible. Unique ear cup design directs sound waves to the ear at a slight angle to create an impressively natural and spatial listening experience.