Integrally-formed finger manipulation skill toy

A finger manipulations skill toy comprising:

• an elongated connecting shaft having a midpoint and a longitudinal axis,
• a first bell at a first end of said connecting shaft, said first bell having a first width in a direction orthogonal to said longitudinal axis, and
• a second bell at a second end of said connecting shaft, said second bell having a second width in said direction orthogonal to said longitudinal axis, exteriors of said connecting shaft, said first bell, and said second bell forming an exterior surface which has cylindrical symmetry about said longitudinal axis of said connecting shaft, said exterior surface having mirror symmetry about a plane through said midpoint of said connecting shaft where said longitudinal axis is a normal vector to said plane, said first width and said second width being equal, said first width and said second width being greater than a width of said connecting shaft at said midpoint, wherein the toy has a length along said longitudinal axis of between 40 mm and 80 mm, outer ends of said bells have a convex radius of curvature of between 7 mm and 15 mm, said elongated shaft has a width between 5 mm and 12 mm, and near a midpoint of said elongated shaft a profile of said toy has a concave radius of curvature of between 25 mm and 45 mm.