Dedicated for professional players and competitive events, the Dunlop Pro are designed as the official balls of the World Squash Federation, Professional Squash Association and Womens Squash Association. Theyre made to last through the toughest conditions, and to ensure the most consistent playability when used by advanced players, thanks to the N-1SR Molecular technology. The diameter of the balls is standard (40mm) and they are supplied in two tubes each featuring 3 balls.