Type 4A resemble an "S" shape. It's diameter is the widest of the 3 sub-types.It retains moisture fairly well but can still be prone to dryness and breakage.
Type 4B hair bends in sharp angles like the letter "Z" . The curl is tighter and less defined - about the circumference of a pen. This hair type can also shrink up to 60% so appears a lot shorter than it actually is.
Type 4C has the most tighest coil pattern and lacks curl definition as seen in type A & B. Coils have to be defined with products and styling with twists or braids. It can also shrink by up to 70% and is very prone to breakage due to the bends in the hair.