The type of sewing thread commonly used is 202 203 402 403 602 603 and so on.
The sewing thread is usually twisted and twisted by a few strands of yarn. The 20, 40, 60, etc. of the sewing thread model are all the count of the yarn. The count of the yarn can be simply understood as the thickness of the yarn. The higher the number, the finer the yarn is; the rear of the model is 2 and 3, respectively, that the thread is made of several yarns and twisted, respectively. For example, 603 is made up of 3 strands and 60 yarns. So the higher the number of stitching lines in the same number of yarn, the thinner the line, the smaller the strength, and the more the threads of the same count yarn, the more the stock, the thicker the line, the greater the strength.
Comparison of line and thickness: