We are excited to be the first tennis ball manufacturer to treat children like young adults! What does this mean? Treat young children like young adults and they respond with more maturity and respect towards everyone around them. So, we made our orange level and green level transition balls with that in mind.3 to a can like regular balls helps children feel like "grown up" tennis players!Acrylic Felt - greater quality and durability than most of the competition.Balls are numbered like regular balls to help children get used to taking responsibility for their own balls.The only transition balls that are numbered like regular balls!