Sony MDR-CD3000 CD Series Headphones with Bio-Cellulose Diaphragm (Discontinued by Manufacturer) Circum-aural design headphones provide stellar sound quality Bio-cellulose diaphragm; neodymium magnets for max power 50 mm diameter driver delivers deep bass and a wide dynamic range Self-adjusting headband and floating earcup system Linear crystal oxygen-free copper litz cord; gold-plated plugs