Wrist Band

Wristbands are encircling strips worn on the wrist or lower forearm. The term can be used to refer to a bracelet-like band, similar to that of a wristwatch, ...

Captains wear armbands so that they can be easily identified by the referees. Captains have to perform special duties during a soccer game, such as calling the coin toss before the game. They also are usually the first person the referee goes to in order to communicate anything from rulings to warnings.