The maximum material principle is a tolerancing principle which states that in the design of two mating parts, a shape or position tolerance can be extended beyond the entered toleranced value. This applies only in the case where the dimensional tolerance is not fully utilized, i.e. play between mating parts is possible. The functionality of the individual parts and their interchangeability in series production remain guaranteed. Thus, the maximum material principle allows tolerance compensation between form or position tolerances and dimensional tolerances. If the maximum material principle is to be applied to a dimension, this is noted in the characteristic control frame as part of the tolerance frame with a special symbol, a capital letter M in a circle. Like other entries in technical drawings, the entry of tolerance principles is regulated by DIN ISO standards. Compliance with the maximum material principle can be checked using a functional gauge. The dimensions of these are based on the maximum material dimensions of the workpiece, on the outside on the largest dimension and on the inside on the smallest dimension. In the case of toleranced elements, any shape or position tolerances entered are taken into account.