Silk fabric has a very magical unit, Momme, the English abbreviation is MM. If people who don't know silk fabrics well, they will think it means millimeter.
In fact, this is not the case, Mumi (MM) is not a direct thickness unit, it is only a reflection of the weight of silk fabric. The conversion between it and gram is 1 m = 4.3056 g / m2.
Silk fabrics are commonly 8m, 12m, 16m, 19m, 30m, which means that the bigger the number, the heavier the fabric, and the price of silk fabric follows the weight, so the thicker silk fabric, the higher the price will generally be.