The Dunlop Pro are competition squash balls featuring the N-1SR Molecular Technology for outstanding durability and playability. These double yellow dot balls are designed with advanced players in mind and have a standard 40mm size. They are the official balls of the WSF (World Squash Federation), PSA (Professional Squash Association) and WSA (Women's Squash Association). The Dunlop Pro are sold as a 6-dozen pack (24 x 3-ball tube).