Each classification term consists of a symbol such as "A01B33/00" (which represents "tilling implements with rotary driven tools"). The first letter is the "section symbol" consisting of a letter from "A" ("Human Necessities") to "H" ("Electricity") or "Y" for emerging cross-sectional technologies. This is followed by a two-digit number to give a "class symbol" ("A01" represents "Agriculture; forestry; animal husbandry; trapping; fishing"). The final letter makes up the "subclass" (A01B represents "Soil working in agriculture or forestry, parts, details, or accessories of agricultural machines or implements, in general"). The subclass is then followed by a 1- to 3-digit "group" number, an oblique stroke and a number of at least two digits representing a "main group" ("00") or "subgroup". A patent examiner assigns a classification to the patent application or other document at the most detailed level which is applicable to its contents.
