The Dunlop Pro are the ultimate performance squash balls for professional, tournament and club players offering the N-1SR Molecular Technology for excellent durability and playability. They are the official balls of the WSF (World Squash Federation), PSA (Professional Squash Association) and WSA (Women's Squash Association) and come in a standard size (40mm). These double yellow dot balls are supplied in a 1 dozen pack (12 balls).