What does 300,600 written on the badminton ball mean?

A+300: Li-Ning A+300 is the ball currently used by the Chinese badminton team for training. Some balls with the "China Li-Ning" stamp are the balls used by the national team for training. The one that everyone usually sees, especially those seen more by golfers in Beijing, should be Li Ning A+300. At the same time, A+300 is also the top ball model sold by Li Ning. A+600: Compared with A+300, Li Ning A+600 is a higher level. It belongs to the national team's internal competition ball and the domestic badminton league ball. Some golfers in Beijing may be able to get some of this ball from the national team, but other than that, there is no sale on the market. Therefore, A+600 is Li Ning’s top badminton that surpasses A+300.