Also known as: racing_silk, 勝負服, 服色
Sportswear worn by any given Jockey during a horse race. These are registered through various controlling authorities, as it is meant to represent the owner of the horse.
In the context of Umamusume, while the concept of jockeys are not a thing in the story's universe, the characters' racing outfit is more often than not a reference to the racing color of their real life counterparts.