The Dunlop ATP Championship Regular Duty Tennis Ball is the official ball of the ATP and the #1 used tennis ball on the tour. They're designed for clay and indoor courts, made with Fluro Cloth, and have unmatched consistency and performance. Each ball case has 24 cans, for 72 tennis balls in total.. Now comes in a new, sustainable package; experience the quality you can rely on while making the planet a better place.