With these tennis balls you can enjoy playing together with your four-legged friend. Playing together will help build a strong bond between the two of you. As many eco-friendly materials as possible have been used for these tennis balls. The balls are made of REPREVE felt and natural rubber. Due to the diameter of 6.3 cm, these tennis balls also fit in various tennis ball launchers. Measurement: Diameter: 6.3 cm – 3PCS