Charleston...naturally the bigger ones are for larger splits and the smaller ones for some of the much more delicate splits that the big pair is just too big for.
I have bought 10+ pairs of split ring pliers over the years. Every time I saw a new design or brand I bought them. I have 3-4 pairs still kicking around somewhere. Then I bought a pair of Xurons. They are so much better than anything else that I have stopped looking at anything else.