Dunlop Pro Squash Balls - 12 BallsThe unrivalled performance, durability and consistency of Dunlop Squash balls are the reasons why Dunlop continues to be the World's No. 1 squash ball. Dunlop is the official ball of the World Squash Federation (WSF), the Professional Squash Association (PSA) and the Women's Squash Association (WSA). All Dunlop balls are engineered with N 1SR construction technology, an elastic hydrocarbon polymer with 12 compounds to create a unique construction