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.