Type 4 natural hair has three categories: 4a, 4b, & 4c. There’s nothing in between 4b & 4c. It’s possible to have two or more different curl patterns. It’s not uncommon, actually!
The curls are not defined when the hair is wet, & when the hair dries, it has a lot of shrinkage & a thick, fluffy feel. The tight coils of type 4 hair can either have a "s" or a "z" curl pattern. "S" curls are most frequently identified as type 4a whereas "z" curls are called type 4b & 4c. If you see characteristics of both hair types, you probably have both.
Based on the Andre Walker Hair Typing System, type 4 hair is called “kinky.” 4b hair has a less defined pattern of curls & looks more like a “z” as the hair bends with very sharp angles. (4c hair isn’t a part of the Andre Walker Hair Typing System.) He comments, “If you can’t identify a defined, specific curl pattern, then your hair type is 4b.”
The NaturallyCurly Hair Typing System calls type 4 “coily,” not “kinky.” It describes it as bending in sharp angles instead of coiling or curling, & says they look like the letter “z.” The curl is tighter & far less defined, having the circumference of an ink-pen. The strands range from wiry & coarse to fine & thin. 4c is describes as being as densely packed as 4b, just with less definition as well as more shrinkage. The texture, which is tightly coiled like all type 4 hair, ranges from super fine & soft to coarse & wiry. It’s incredibly delicate hair.