The largest frame for the Nellie Snellen square multi-frames set is 8.6 cm which converts to just a shade under 3-1/2". This particular set comes as a set of 3 dies: see
here for a visual The smallest die in this is set is 4.9 cm which is just under 2".
For Spellbinders
Lacey Squares, there are 5 dies and the sizes are as follows:
1: 1⅛"
2: 1⅝"
3: 2⅞"
4: 3�"
5: 4"
So you can see that the Spellbinders are a little bigger plus you get more dies compared to the Nellie Snellens.
Hope this helps!