The original SanDisk MP3 Player has an option none of the models that followed contains: replaceable AA battery.
This one option makes it an ideal partner for the road and for use daily.
It allows one to resupply the device with energy at a moments notice, if you have an extra AA battery in your case/backpack, or can purchase extra energy from numerous places on road.
I do wonder why this one option was removed in persent and future models.
SanDisk should bring it back.