Introduced to set the standard as the shape of the Sony MD Walkman®. Quite compact, this player was modeled on a MiniDisc case. It was the slimmest, smallest, and lightest unit in the industry at the time—a revolutionary size small enough to slip into one’s breast pocket or bag without feeling bulky. A new finishing technique gave the unit a distinctive character, in sparkling colors. Three color options were subsequently introduced. Energy-efficient circuitry enabled operation at only 1.5V.