An exercise ball, also known as a stability ball, Swiss ball, or yoga ball, is a large inflatable ball made of soft elastic material, typically PVC. It is used for various exercises to improve strength, balance, flexibility, and core stability. Exercise balls come in different sizes to accommodate different body types and exercise routines. They are versatile fitness tools and can be used for a wide range of exercises, including abdominal workouts, Pilates, yoga, stretching, and resistance training. Exercise balls provide an unstable surface.