As far as I know, all the Sony PRS-505 series have the same batteries and the same number of page turns. Any Letters after the Model depict the colour and whether it is a special edition. Example:
From sonystyle.com
- PRS-505/RC (Colour is Sangria Red)
- PRS-505/RC/DC (Colour is Sangria Red, Preloaded with Danielle Steel eBooks and embossed cover)
- PRS-505/SC (Colour is Silver)
- PRS-505/LC (Colour is Dark Blue)
From sonystyle.ca
- PRS-505 R (Colour is Sangria Red)
- PRS-505 S (Colour is Silver)
Why they have different model numbers in different countries I'm not sure.
I've never seen a PRS-505/S/CEW model but I assume it is Silver in colour and a special edition of some kind.
I have seen other PRS-505 models that have been preloaded with a certain author's eBooks and one that had a .007 embossed cover on it but I don't know if they had different model numbers.
Hope this is of help. WDE.