The Penn Championship Titanium tennis balls feature an extra-duty felt making them perfect for intense play on hard courts. These highly visible balls offer great consistency and feel and have a natural rubber core for increased durability and optimum playability. Benefiting from a thicker grade of felt and improved core pressure retention, the balls guarantee longer-lasting play and reduced wear. They are approved by USTA (United States Tennis Association) and come in a 12-dozen pack (144 balls).