ISO 14405-1:2016 establishes the default specification operator (see ISO 17450‑2) for linear size and defines a number of special specification operators for linear size for features of size, e.g. "cylinder", "sphere", "torus,"[1], "circle", "two parallel opposite planes", or "two parallel opposite straight lines".

It also defines the specification modifiers and the drawing indications for these linear sizes.

It covers the following linear sizes:

a) local size:

- two-point size;

- spherical size;

- section size;

- portion size;

b) global size:

- direct global linear size:

- least-squares size;

- maximum inscribed size;

- minimum circumscribed size;

- minimax size;

- indirect global linear size;

c) calculated size:

- circumference diameter;

- area diameter;

- volume diameter;

d) rank-order size:

- maximum size;

- minimum size;

- average size;

- median size;

- mid-range size;

- range of sizes;

- standard deviation of sizes.

ISO 14405-1:2016 defines tolerances of linear sizes for the following:

- a + and/or − limit deviation (e.g. 0/−0,019);

- an upper limit of size (ULS) and/or lower limit of size (LLS) (e.g. 15,2 max., 12 min., or 30,2/30,181);

- an ISO tolerance class code in accordance with ISO 286‑1 (e.g. 10 h6);

with or without modifiers.

ISO 14405-1:2016 provides a set of tools to express several types of size characteristic. It does not present any information on the relationship between a function or a use and a size characteristic.

[1] A torus is a feature of size when its directrix diameter is fixed.