Soft weights are designed for strengthening, plyometrics, balance training, and mobilisation exercises. In addition to offering a more fluid range of motion to using a standard dumbbell, the soft weight design is safer, reducing the risk of damage or injury if the weight is dropped. The shape also helps to promote the development of functional grip strength. As the size of the ball does not increase as the weight increases they offer a consistent grip as you progress to heavier weights. DOP Free PVC outer shell with sand filling. Phthalate Free. Diameter 12cm.