S is the British system number, which refers to the weight of a pound of yarn under the common moisture regain rate, its length has a few 840 yards, called several yarns. The yarn count of staple is denoted by S and Spun by English. The thicker the yarn, the smaller the S value; The finer the yarn, the greater the S value, for example, 40S is finer than 20S.
D is an abbreviation of Denier, a fineness representation of chemical fibres, and refers to the weight in grams of a 9000m filament at a constant moisture regain. The number of Filament is expressed as D in general, and Filament is also called Filament in English. The larger D indicates the thicker yarn, for example, 75D is thicker than 50D
Tex, also known as the "number", referred to as the special, the old public branch. It is the weight in grams of 1000 meters of yarn at a constant moisture regain.
The metric number of Nm refers to the meter multiple of the length of 1 gram of heavy yarn under a common moisture regain rate, that is, 1 gram of heavy yarn is exactly 1 meter long (metric) yarn, 1 gram of heavy yarn is 200 meters long, and the fineness of yarn is 200. The metric number is also a constant weight system, so the larger the number, the finer the yarn.
A dtex, short for Tex, is the number of grams in a bundle of fibers 10,000 meters long.
