Now available in Blue! Are you looking for the perfect size Pilates or Reformer accessory ball? If you are looking for an alternative to a pad or circle, the 4" mini ball is the solution! Re-inflate or deflate it to your own requirements, and use it during exercise to engage the body's core muscles. The MINIBALL is a durable 4-ply fitness tool to help you also strengthen the inner thighs and deep abdominal muscles during workouts, taking pressure off of the Iliotibial bands on the outside thigh, and making you leaner and more toned.