First of all, the general unit is called: Denier, abbreviated as "Denier", which is represented by the letter D, indicating that the weight of the fiber at 9000 meters is 75D, and there is 350g per 9000 meters of fiber. Another standard unit uses the name: decitex, which is represented by the letter "f", Dtex is decitex, 1 decitex =9/ 10 denier, representing the weight of polypropylene filament with a length of10000m. The larger the size of the same fiber, the thicker the filament. In our example, 75D/72F: F in fine denier polypropylene filament stands for monofilament, which means that there are150g fine denier polypropylene filament every 9000m, which consists of 72 monofilaments.