There are two main types of tolerances defined in ISO 2768:

For symmetry and circular runout, the tolerance is equal to the numerical value of the geometrical tolerance class (e.g., Class "m" = 0.5mm tolerance zone), but never less than 0.01mm.

ISO 2768 is the international standard for , used to simplify technical drawings by providing default values for dimensions that do not have specific tolerance indications . It is primarily applied to parts produced by machining (metal removal) or sheet metal fabrication. Core Structure of ISO 2768

6 to 30mm: ±0.2mm