One pound is equal to 0.4536 kg. When you say about 20, you generally mean British yarn. Specifically, if the length of a yarn (single strand) 1.693m is exactly equal to one gram, it is defined as one. If 1S (one strand) is divided into 20 yarns, then each yarn is a 20S yarn.

I don't know if you understand. On the contrary, it is divided into 30 portions, and each portion of yarn is 30S yarn. The bigger the number, the thinner the yarn! What you said should be 20S/2, which refers to the blended material of two 20S yarns, flax and cotton. It is estimated that the weight per square meter or square yard is 12 pounds, and one yard is equal to 0.9 144 meters. Hehe, I wonder if you can understand my explanation!