The transition occurs once the cotton fiber passes through a carding machine (which opens, cleans, and partially aligns the fibers into a sliver) or a combing machine (which additionally removes short fibers). Cotton in sliver, lap, or roving form that has been carded or combed belongs here, not under the raw cotton heading.

This heading covers carded or combed cotton regardless of whether it is in sliver, lap, or roving form, as long as it has not yet been spun into yarn. All of these intermediate forms fall under the single subheading 520300. Classification only shifts once the material is twisted into yarn, at which point the appropriate cotton yarn heading applies.