This solid ball sand ball has many advantages. It is made of soft PVC material on the outside, which is comfortable and skin-friendly, with good grip and anti-skid properties. The internal filling is iron sand, which distributes the weight evenly. The ball can be inflated, allowing for flexible adjustment of firmness and volume, making it suitable for a variety of training scenarios. Moreover, it is safe and durable, less likely to cause harm, and is easy to maintain on a daily basis, offering excellent value for money.