From the Manufacturer MDW-60M 60-minute ES MiniDisc provides the highest level of performance: random access, portable, and virtually unshockable. Sony MD is the absolute best way to record your music. Sony's best MiniDisc, MiniDisc ES is high grade for lower error rates. User-friendly sleeve case keeps your disc and data safe. Sony put a special protective layer on each disc for smooth magnetic head contact. This is a single Sony 60-minute MiniDisc.