The Vollint Premier tennis balls are designed for competition-level play, match use and coaching. These premium tennis balls are filled with pressurized air to reduce the weight, move faster through the air, and deliver great bounce and spin characteristics. Featuring a durable rubber core and a thick, bright yellow extra-duty felt, the balls have a longer lifespan and guarantee increased visibility on the court. Made with a quality UK woven wool cloth, they ensure optimum playability and consistency on all court surfaces. The Premier balls are supplied in a pack of 12 dozen (144 balls).