<p>It has two compartments. The bottom one is for water or sand to add weight to keep it stable on the ground.</p> <p>The upper is for air so you can train your skills.</p> <p>The base can be filled with sand or water for stability.</p> <p>Sand has been shown to be more effective in older children.</p> <p>Durable vinyl construction withstands impact and keeps bouncing forward.MULTIFUNCTIONAL: This fun inflatable punching bag is perfect for fitness and stress relief. Improve coordination and flexibility, burn Burn calories and reduce stress while improving mobility and hand-eye coordination. The back and forth swing on each punch is also great for kickboxing workouts. Available for adults and children.</p> <p>Lightweight and Durable: This target is made of premium PVC material, which is lightweight and durable, with a thickened bottom design for portability. The hanging design of the durable bag allows you to move to where it matters most most comfortable - perfect for your home or commercial gym.</p> <p>Fitness punching bag: fun for the whole family. Easy to inflate and deflate, folds small for easy storage. This boxing ring trains coordination and reflexes - losing weight is fun - and no more sweating in the gym. Eliminate stress and depression. Practical, safe and ideal as a boxing trainer for children as there is no risk of injury.</p>