Which is not part of a referee's uniform?

The correct answer identifies an item that does not belong in a referee's uniform. Referee uniforms typically consist of a standardized black and white striped shirt, black pants, and a whistle, which is essential for signaling during matches.

The inclusion of black wrestling or gym shoes with colored highlights does not conform to the traditional referee uniform. Referees are expected to wear shoes that are functional and professional, typically all black, to maintain a neutral appearance on the mat. Thus, the choice highlighting colored features is not in line with the uniform standard, which emphasizes a consistent and professional look.

This understanding of referee attire is essential for maintaining the integrity and professionalism of wrestling matches, ensuring that officials are easily identifiable and are taken seriously in their role.