 Downloading more than 4,000 tracks to the device can destroy its internal library, so that its disk space cannot be used properly in most cases.Originally released in 2003, the YP-55 is a flash-memory based player featuring a rotating top which operates the Fast-Forward/Rewind functions and prevents accidental usage.It was available with built-in memory sizes of 128 MB (YP-55H), 192 MB (YP-55I – sold only in Canada), 256 MB (YP-55V) and 512 MB (YP-55X).