The primary difference lies in their shape and practical application: 

• AquaBag Cylinder: Ideal for exercises involving linear movements, such as lifts and presses. It focuses on strength training, postural stability, and endurance. 
• AquaBag Ball: Better suited for dynamic exercises requiring rotation and balance, such as throws or multi-directional movements. It targets dynamic balance and coordination. 

Both use water movement to create variable resistance, making them complementary for a wide range of workouts.