The Balls

Balls
The international rules specify that the game is played with a light 2.7 gram, 40 mm (formerly 38 mm) diameter ball. The ball is required to have a coefficient of restitution of 0.4. The 40 mm ball was introduced at the 2003 World Table Tennis Championship. However, this created some controversy as the Chinese National Team complained that this was merely to give non-Chinese players a better chance of winning. A 40 mm table tennis ball is slower and less "spinny" than a 38 mm one. The ball is made of a high-bouncing gas-filled celluloid ball, colored white or orange, with a matte finish. The choice of ball colour is made according to the table colour and its surroundings. For example, a white ball is easier to see on a green or blue table than it is on a gray table.

New poly balls
As of July 1, 2014, all ITTF events started using Plastic Polystyrene 'Poly' balls. The playing characteristics of the new balls are unique but very similar to celluloid. Poly balls transport more safely, and are environmentally friendly. Non-poly balls are still legal for tournaments and it is up to national and regional table tennis governing bodies to determine what type of ball to use for their tournaments. All poly balls on Megaspin have "Poly Ball" in their name. Balls have a rating system that uses stars. Ranging from one to three, the best balls and the only balls you should use for most purposes are the three stars. These can be purchased in packs of 3 or 12 or in bulk. 1-star, 2-star and training balls are less durable and break easier. Good quality balls last a long time when given the proper treatment.

Extending the Life of Table Tennis Balls
To ensure that you get the most out of each ball, make sure to keep it out of: direct sunlight, excess heat, and excess moisture. Also be sure to pick up the balls when they fall to the floor, so you and others avoid stepping on them. The three-stars should be used for most rally drills and practice games. For multiple-ball drills, such as serves and smashes, good quality practice balls or 3-star bulk packs can be purchased.

Color
The color of balls don't matter much for games and practice, just be sure to use a color that is the most visible given the conditions. The legal colors are: white and orange.