From a prior post 

"It provides the means for high-bandwidth, near CD-quality, stereo audio playback from a CompactFlash(R) (CF(R)) cartridge, other removable flash memory or embedded flash memory in a portable electronic unit. Record, edit and playback functions are encoded in the unit and a PC interface links the portable unit to the computer."

The type of memory matrix is important....e.Digital prefers NAND or any serial type memory.

doni