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.