symmetry
Definition The tolerance zone is limited by two planes which run both parallel and symmetric to the datum axis or the datum plane and are a distance t apart.
symmetry
DIN EN ISO 1101
symmetry
Example The median plane of a slot shall be contained between two parallel planes which are 0.08 apart and symmetrically disposed to the median plane with respect to the datum feature A. Note For symmetry tolerances of a line or an axis, see ISO 1101.