This is the Dunlop FORT hard court tennis ball. For over 60 years, it has been the standard match ball used in major domestic tournaments. It is characterized by its uniformity, allowing players to play with the same performance and feel with every ball. It achieves a mild hitting feel and excellent durability. It is an International Tennis Federation approved ball and a Japan Tennis Association approved ball. I have used only one of the four balls. The other three are unused. Please check the condition in the images.