A fitness and recovery revolution The tidal tank is the only fitness product that responds directly to how you move. Lift the tank and the smallest angle will ensure that the waterfalls from one side to the other. As soon as this happens, your muscles have to respond immediately and more importantly: work closely together to stay in balance. All this results in the perfect functional workout, it solves problematic movement patterns, prevents injuries and however you use it, it trains your entire body. Fill the bag up with water to reach the desired weight. The max weight of the bag is about 25 pounds, but you'll want to leave room for air. The more air you have in the bag, the more instable the weight will become. Bullet Points: 1?HOW TO FILL: Fill water (under a faucet or with the tube provided - make sure the pin is down for this), then push the pin in the up position to open it for the air, attach the pump and start rocking it, the fuller it is, the heavier and more stable it becomes. Less water makes it lighter but more unstable. 2?STRONG AND DURABLE: Are you ready for a hard full-body workout? Weighing only 2 .8lb when empty. Fitness water bags are easy to transport and prepare for exercise. Fitness water bag with water are super tough fitness sandbags, filled with air and water. Valve makes it very easy to fill and empty the bag. 3?MULTIPLE FUNCTIONS: Get this training for your core, legs, arms. Different handle positions allow for variety in your exercises. When full weigh up to 25 lbs! 4?PORTABLE AND VERSATILE: Our fitness water bag is perfect for cardio, high-intensity interval training for CrossFit and all Olympic movements such as lifts, swings, curls, step-ups and rows. 5?TRAINING EQUIPMENT: Get the full-body workout through instability. Pick up the tidal tank and you immediately feel its unforgiving properties. The entire weight of the water sloshing from one side to the other in response to the smallest tilt. In order to raise it above your head, even the smallest muscles are activated, working together with the bigger muscles to maintain balance and power. Because of this, even 15 pounds of water can humble trained athletes. Specification: Material: 840D TPU, airtight and leak-proof Size: about 42x18.5x10cm / 18.8x7.4x4inch Empty package weight: about 1.3kg / 2.8lb Packing List: 1 * Fitness Water Bag