Type 4 hair is a hair type that is usually common among African-American women and is considered the densest hair type. It is also known as kinky or coily hair and is further divided into three subcategories: 4a, 4b, and 4c hair. The subcategories are based on the width or diameter of the wave, curl, or coil pattern. Type 4a hair has medium-sized, loosely packed curls that have a springy S-shape and are about the size of a crochet needle. Type 4b hair has densely packed curls that are tighter than 4a and resemble tight curls that aren’t as tight as the 4c curls. Type 4c hair features unapologetically bold coils that are sublimely springy and has the tightest curl pattern of all hair types. Type 4 hair may be a bit more high-maintenance than other curl types, but it responds beautifully to the right routine.