Marshall identify page

[lpwcruzr]

somewhere I remember seeing a web page that had a breakdown of some of the marshall models. I can't find the link by using the search. Anyone know what I'm talking about? Or if someone can explain some of the differences in teh 900s that would be good. What is a slx? How is that different that a plain 900? I found a 2x12 900 combo with 2 volumes and 2 reverb controls in a music store I'm going to go and tryout. but I also see a couple slx for sale as well.