Level iv is extra strong.
Togu dynair ballkissen xxl cushion (level iv), 20" diameter, black with the dynair ballkissen xxl you can feel and train the deeper laying musculature. The dynair ball cushion xxl level iv is a brilliant tool for professional athletes, high level coordination and stability training. High level coordination and stability training. the difference between the dynair ballkissen level vi to level iii and meditation is the degree of stiffness of the material.