The CanDo® Wate™ Ball is small enough and flexible enough to grasp with 1 hand, but it is also big enough to hold with 2 hands. Each Wate™ ball has the same diameter of 5", no matter the weight of the ball. Also, the Wate™ Ball is soft and give enough to comfortably conform to your grasp. Plus, each ball can be inflated and deflated with a regular bicycle pump to make the ball harder or easier to grasp. You can purchase individual Wate™ Balls or purchase them in a set of 6 balls (weights tan through black).