The document describes the structure and hierarchy of headings, subheadings and sub-subheadings in the Harmonized System for classifying goods. It provides examples to illustrate how:
1) A heading can be divided into 1-dash subheadings which are further divided into 2-dash subheadings, and so on to create multiple levels of subheadings.
2) Lower level subheadings provide increasingly specific descriptions of the products classified under higher level subheadings.
3) Subheadings at the same level of dashes can be compared, but not subheadings with different numbers of dashes.