This ball looks small, fills my hands (Size 9) but good for a variety of exercises. In the level "blue" he admits after not too much.
For users with genuine hand problems he is u. U. too unruly, for polynuclear Zupacker perhaps too soft. The textured surface makes it handy, prolonged use my copy is minimally tacky, but he did not müffelt by solvents or plasticizers. Washable the balls also.
