A ping pong ball weighs 2.7 grams, which is the required weight for Olympic competition as stated on the Table Tennis Master website. It is hollow, made of celluloid and filled with gas.
Ping pong balls are white or orange, and they are sold according to a three-star rating. Three-star balls are of the highest quality and are used in competition. The mandatory diameter of a ping pong ball for competitive play is 40 millimeters, which The International Table Tennis Federation mandated in 2000. The ITTF believes that a larger ball slows down the pace of the game, making it easier for television viewers to follow the game.