Okay, I noticed that some people are giving the wrong hair type out. Let's start with the 3's
3a - the circumference of a side walk chalk or a banana

3b- a tighter curl, the circumference of a child's marker

3c- tight ringlets, the circumference of a PEN ! (a pen fits inside of the curl)

4a- quite a bit of shrinkage, very pretty. The circumference of a COFFEE STRAW !!!


Hope I helped clear a few mistakes up