Penn ATP World Tour™ Regular tennis balls give players a consistent feel and bounce time after time, ball after ball. This ball takes to soft court surfaces with as much swiftness as extra duty balls on hard courts. Highly visible felt coupled with a superb, lively feel make this a top choice for elite players. Recommended for play on soft court and indoor surfaces, carpet, clay or grass. Made with Smart Optik® Felt by Tex Tech for 19% more visibility. USTA and ITF approved. Each can contains 4 tennis balls. *Note: Penn ATP World Tour Regular Duty tennis balls are an update to Penn ATP Regular Duty balls, featuring a new name and updated packaging.