A rugged surface is good for massaging your skin to stimulate blood circulation, relax nerve endings, and strengthen body agility. You can use the two sides of this product for different purposes. The top rugged surface is used for foot massage, the bottom surface is used for balance practice. There are anti-slip circles at the bottom of this product, ensure your practicing safety, and there is a gas nozzle, you can inflate it by yourself. You can practice yoga with this foot massage ball, it can help you release your muscle and relieve your tension. This product is made of qualified PVC material, safe, pliable and comfortable. Package included: 2 x Foot Massage Balls.