The Layering Framelits from Stampin’ Up! have lots of pieces that allow you to make layers of just about any size you want. But they are so close in size that the Framelits need to be stored every-other-size to nest together. It can get very confusing to figure out figure out which one is which.
Taggers will help you name the Framelits. Each piece gives a name for each piece, shows the name and item number for the set, and also shows the size of the finished piece. They will help you pick a Framelit when creating.