AMERICA'S #1 SELLING BALL: The product of 100 years worth of testing and perfecting; Penn produces the best selling line of tennis balls in America. GREAT FOR BEGINNERS: The Control Plus kids' tennis ball features slightly lower compression for controlled bounce and 25% reduced speed. An ideal junior ball for the first time playing on a 78' court. MASTER THE BASICS: Penn reduced speed tennis balls are great for players of any age still mastering proper ball control. 25% reduced speed allows for longer rallies and better practice. USTA APPROVED: A high quality and consistent ball, Penn Control + is approved by the USTA for the 10 and Under Tennis Program. LASTING DURABILITY: Durable felt ensures the all courts tennis balls will play like new for as long as possible.