It would have been fairly obvious from holding it in your hand at the store ;) It does call itself MD2-HD which is the abbreviation for Mini Disk, 2 sided, Hig

It would have been fairly obvious from holding it in your hand at the store ;) It does call itself MD2-HD which is the abbreviation for Mini Disk, 2 sided, High Density. Mini disk here means 5.25". 3.5" disks were MF "Micro Floppy", as in MF2-DD or MF2-HD.