References used introduction

OUTFIT AND EQUIPMENT FOR WATER POLO
The ball for water polo has a round shape and an air chamber with a closing nipple. The weight of the ball has to be ranging from 400 to 450 grams. The circumference of the ball for games of the men's teams is 0.68 — 0.71 meters, and for games of the women's teams is 0.65 — 0.67 meters.

Cap with ear protectors protects players from powerful ball strikes. Hats are fastened under the chin and not removed until the end of the game. Usually one of the teams plays in white hats, and the other is in blue ones. Hats of goalkeepers are painted red.
Little player equipment is needed to play water polo. Items required in water polo include:
Ball: A water polo ball is constructed of waterproof material to allow it to float on the water. The cover is textured to give players additional grip. The size of the ball is different for men's, women's and junior games.
Caps: A water polo cap is used to protect the players' heads and ears, and to make them identifiable from afar. Home team field players wear numbered dark-colored caps; Visiting team field players wear numbered white caps. Both starting goalkeepers wear red caps (sometimes quartered), numbered "1" (substitute goalies' caps are numbered either "13" for FINA international play or "15" for NCAA play) Caps are fitted with ear protectors. Male swimsuit (left) and Female swimsuit (right)
Goals: Two goals are needed in order to play water polo. These can either be put on the side of the pool, or in the pool using floaters.
Mouthguard: A mouthguard is not mandatory in most tournaments but is recommended.
Swimwear: Male water polo players wear either swim briefs or jammers (thigh-length trunks). Female players must wear a one-piece swimsuit. Suit-grabbing fouls are common, so players often wear tight-fitting suits, and may layer on several suits at a time for additional security. Many swimwear labels also sell specialized water polo suits that feature reinforced stitching and tougher fabric. Female water polo suits are generally one-piece outfits which do not have open backs, but zip securely up the back so as to not have straps that can be easily grabbed.