These models are made possible by SONY’s closed vertical-in-the-ear design, which vertically aligns the 13.5 mm driver with the ear channel. A new bushing design brings the cord outlet closer to the face, reducing the weighting on the earpiece when the cord is pulled. This, coupled with a “stay-in” design that uses a soft, hollow elastomer part which sits in a pit inside the antitragus, means both an ideal fit and lower likelihood that the headphones will fall out. The driver housing features a seamlessly smooth shape with a mirror-like finish achieved using a metal deposition method.