This document specifies two methods of indicating the composition of yarns, whether single, folded, cabled or multiple wound. The notation comprises linear density indicated in the Tex system, number of filaments in filament yarns, direction and amount of twist, and number of folds.

This document is not applicable to some special kinds of yarns, for example to fancy yarns, textured or bulked yarns or yarns produced by wrapping a textile or non-textile material round a core. It is not applicable to yarns with other features such as constituent fibres, after treatment and type of package.