Penn Coach Teaching Tennis Balls are ideal for practicing your skills, or for a casual or competitive game on the court. These Penn tennis balls come in a bright yellow color that helps improve their visibility, especially on bright, sunny days. This makes it easier to track their movement, hit them and control the placement on your shots. The practice tennis balls are ideal for training sessions with a coach or a machine. Durable felt ensures the all courts tennis balls will play like new for as long as possible.