Would you be willing to answer a few brief questions about PlayStation Forums?
Go to Solution.
it's on the back after the serial number.
Model# CECH-2001A, CECH-2001B, CECH-2101A, CECH-2101B, CECH-2501A, CECH-2501B, CECH-3001A, CECH-3001B
All other models
Rules of Conduct__The PlayStation Forum Team__Customer Support
Once you have the model number you can check out the university of Wikipedia - there is a table of the various models.