5 cm: (suitable for children to play; can also be used to exercise the elderly flexible use)
6 cm: (suitable for children to play; can also be used to exercise the elderly flexible use)
7 cm: (suitable for children to play; can also be used to exercise the elderly flexible use)
8 cm: (suitable for girls who will play; also for just learning to play with friends)
9 cm: (for everyone who will play: also suitable for learning to play men's friends)
10 cm: (standard stage performance with the ball)
