Most of those use a common embedded board. Its an ARM9 cpu, 640x480 display, Windows CE (various versions... We have a CE 4.2 based unit at work that looks very similar to this one). In fact the one we have shares the same board with a 7" android tablet (also crap). 9V chargers are common with these, often undersized to charge the battery. Also the battery protection circuit is *horrible* on most of these if you ever let the battery go flat. Basically the protection IC will cut itself off from the battery, and requires manual resetting & charging.
We bought one used for $5 off someone, just to have an example of what not to buy. (I work at an independent computer store.)
