These Umpire (Ump) pants are made of a dry cotton blend from the USA and Australia, using yarns spun in a way that creates neps by adjusting the machine when carding the raw cotton (a process to remove impurities and align the fibers in a certain direction). This is a very technical process, and it is difficult to get the neps to be strong or weak. On the other hand, it has a natural and rustic look. Since nep yarn is a weak yarn that breaks more easily than usual, delicate control is necessary when weaving. Therefore, Jackman uses an old-fashioned "rapier loom," which is capable of weaving with strength on weak yarns such as silk. With the motif of umpire pants, large pockets run from the waist to the hips that look like they were used to store spare baseballs while the waist features an elasticated drawstring.