The Tretorn Serie+ Tennis Balls feature extra durability on all court surfaces provided by a special mix of wool, cotton and synthetic fibres. Serie+ balls are the first tennis balls in the world with a unique TRI-TEC sealing membrane, which is used to retain air and keep balls pressure significantly longer than any conventional pressurised ball.
ITF Approved
Official Ball of ATP World Tour and ATP Challenger Tour.
Style no. 473607