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.