Originally Posted by
diskus69
Thanks everyone for the replies. After some further digging It seems the terminology is "1 way release" and "two way release". They also have "multiple release" and "instant release". What I found more challenging is to find exactly which features are found on which models of shifters, especially past models.
I think you only need to worry about how many cogs are on the cassette and whether you have a "Dyna-Sys" derailleur or not. (Shimano changed the cable pull ratio when they introduced Dyna-Sys 10-speed stuff)
The labels that Shimano puts on stuff is marketing-speak. It's mostly meaningless except to differentiate "this year's stuff" from "last year's stuff".