The world's first compact disc player. Careful consideration of the features led to a design with large buttons for the controls (play, pause, fast-forward, rewind, and so on). By the time the product was finalized, the vertical loading format presented at the prototype stage had been completely overhauled into a horizontal format, which successfully distinguished this unit at launch from competitive models that followed the original format. Over time, successors to the CDP-101 yielded strong sales. Recordings of digital audio signals on compact discs introduced truly revolutionary sound quality at the time, marking the dawn of a new age in digital audio entertainment.