The traditional performance standard, the Wilson(R) Championship Extra Duty Tennis Balls feature exclusive Dura-Weave felt for enhanced durability and ultimate performance. Tennis Ball Pack Extra Duty balls built for longer playing performance on hard court surfaces Exclusive Dura-Weave felt for greater durability and enhanced feel High-altitude core for best performance on courts above 3500 ft. Additional Details Includes 60 total tennis balls 20 cans of 3 balls per can