Dunlop’s official tennis balls used for Australian Open are here!! The Dunlop AO Tennis Balls include an HD Core, a remastered form of the exemplary Dunlop Forte Core intended to play much more reliably and with more prominent toughness. Additionally, Dunlop has additionally added an HD Pro Cloth to the ITF Approved balls, a top-notch felt built for the largest amount of play. About Dunlop: Dunlop’s tennis balls are the official ball of the Bavarian Tennis Federation. Up your game with a super-premium ball.