2.2 Balls, chalk
- The balls consisiting of three must be of a material and of colours admitted by the UMB committee. The required details are published by the committee at the end of chapter I of the world organization rules.
- These balls are rigorously round and their diameter must be between 61 and 61.5 cm. A ball's weight must be between 205 and 220 gramms or must have another weight agreed by the UMB committee. However, the difference between the heaviest and the lightest ball should not exceed two gramms.
- The chalk should not excessively soil the surface of the game.
