I found out more info on the ACTRON CP9125 POCKETSCAN OBD II CODE READER/ERASE (released in Oct 2004)

The pocket size is just for checking and erasing codes. I got a new one for $50 on ebay.

There are 3 more advanced ones that are hand held and they get more into checking emissions, and reading older types of cars.

Bottomline: the ACTRON CP9125 POCKETSCAN OBD II CODE is fine for checking codes.