Dunlop fort clay court tennis balls the dunlop fort clay court tennis balls are designed for match use on clay surfaces thanks to the dunlop hdurability core for long lasting shape retention and playability making them perfect for players of all levels these dunlop tennis balls also benefit from a clay guard outer for greater durability complete with the bright his viability design making them perfect for low light conditions tennis balls 4 pack hdurability core dunlop fort m