A Water polo cap is a piece of headgear used in water polo

Water polo

Water polo is a team water sport. The playing team consists of six field players and one goalkeeper. The winner of the game is the team that scores more goals. Game play involves swimming, treading water , players passing the ball while being defended by opponents, and scoring by throwing into a...

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The caps are used to protect the ears from injury possibly caused by a water polo ball

Water polo ball

A water polo ball is a ball used in water polo and canoe polo, usually characterized by a bright yellow colour and ease of gripability, so as to allow it to be held with one hand despite its large size.-Standard water polo ball characteristics:...

 hitting the ears at high speed. They are also used to identify the player, using the number on the cap.

Caps are differentiated by the number printed on them as well as the color. Players from the visiting team will wear light colored caps, whereas the home team players will wear dark caps.

The goalkeepers wear quartered red caps, numbered "1", while substitute goalies have caps which are either numbered "1-A" in NCAA games, or "13" in FINA

Fina

Fina may refer to:*Fina, a character in the Skies of Arcadia video game*FINA, the International Swimming Federation*FINA, the North American Forum on Integration...

 international games.

Underwater hockey

In underwater hockey

Underwater hockey

Underwater hockey is a global non-contact sport in which two teams compete to maneuver a puck across the bottom of a swimming pool into goals.-Play:...

, water polo caps are worn by competitors to help make the teams distinct from each other, and to offer some protection to individuals against the possibility of a burst eardrum caused by the blade of a swimfin

Swimfin

Swimfins, swim fins, fins or flippers are worn on the foot or leg and made from finlike rubber or plastic, to aid movement through the water in water sports activities such as swimming, bodyboarding, bodysurfing, kneeboarding, riverboarding, and various types of underwater diving.Scuba divers use...

 making direct contact across the ear. Opposing teams wear either light or dark caps, whilst the water referee

Referee

A referee is the person of authority, in a variety of sports, who is responsible for presiding over the game from a neutral point of view and making on the fly decisions that enforce the rules of the sport...

s wear red caps as well as bright (often yellow) shirts and orange gloves.