The CanDo Wobble Ball can be used for vestibular stimulation, core training, and general balance exercises. You can adjust the level of difficulty by adding or removing air from the Wobble Ball. Use the dome curved-side down as a seat, rocker board, or to kneel on for vestibular activities. With the flat side down, use the Wobble Ball for balance, core and strengthening exercises. 18" diameter with a 200-lb. weight limit.