[rcentros]

I think the oldest working eReader I own is a Sony PRS-505 (originally made in 2007, but not discontinued until 2009). I guess, technically, the M-500 "works" if you consider the battery going dead within five minutes "working." I also own an Astak EZReader Pocket Pro that has an amazingly good battery for its age (stays charged in "standby" for about two months). About the same age is my Sony PRS-300 (Sonys mostly have good batteries). I also have an Ectaco JetBook "Reading Device," but I have no idea how old it is because they made (or at least sold) these for quite a while. The battery is good on that one too. Also an Ectaco JetBook Lite, which will never will have a battery problem since it uses two AA batteries. Again, I have no idea how old it is. These can still be bought Ectaco (along with the JetBook Mini) but I'm guessing both are very "old stock."

I've attached three images of the Sony PRS-505 and Astak EZReader Pocket Pro. Sorry about the quality.