Newly developed, encapsulated, dynamic Stereo Insidephones equipped with 8.5 mm-diameter compact driver units. In order to achieve impressive high sound quality reproduction, we employed machined, full-aluminum bodies. This was also intended to heighten the satisfaction of ownership and use. Wearability has been improved through the use of an angle adjusting mechanism and three different sizes of earpieces. Low sound leakage allows for use in public spaces. Tangling of cords on storage is prevented by the housing coupling mechanisms in both earpieces.