Providing outstanding performance and great value for club play. Standard size with a 10% longer hang-time than the Pro. The 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). Top Quality Squash Balls providing great performance The Dunlop yellow dot, also known as the Dunlop Competition ball. This is the same diameter as the Pro ball, but a bit bouncier. This is perfect for improving players or just cold courts. Seriously, if the ball isnt bouncing around enough, give the single dot a try. I was actually playing with one the other day by mistake and didnt notice until the third game. So its a subtle difference and can make the game more enjoyable by making the rallies longer.