Features: Simply slip it over the support for hard use. ■ Simply slip over the top of the hard support (6.0 inches / 15.25 cm) to use as a large ball (6.7 inches / 17.25 cm). ■ If the diameter is within 0.8 inches (20 mm), it can also be used with other supports other than our company. ■ The groove depth is 2 levels, so you can adjust the height according to the support you use. (Utility Model)