The Kamagon Ball Evolve is a unique core stability product that bridges a necessary gap in the functional training market. The Kamagon Evolve is filled with water to adjust the weight creating a “hydro inertia” that recruits a greater number of muscle fibers when performing the most basic to advanced exercises. Water lines imprinted on the ball allow for accurate water measurement*. The Kamagon Evolve is used for full body workouts engaging in full range of motion exercises. Proudly made in the USA. The Kamagon Ball Evolve is a unique core stability product that bridges a necessary gap in the functional training market. The Kamagon Evolve is filled with water to adjust the weight creating a “hydro inertia” that recruits a greater number of muscle fibers when performing the most basic to advanced exercises. Water lines imprinted on the ball allow for accurate water measurement*. The Kamagon Evolve is used for full body workouts engaging in full range of motion exercises. Proudly made in the USA. The 14″ Kamagon Ball holds 1-45 lbs. of water. The 9″ Kamagon Ball holds between 1-13 lbs. of water. For orders of 10 or more, or orders outside the continental United States