The ball is made of foam material that absorbs a considerable amount of water. So you need to squeeze it every now and then to release it. This resulted in creating cracks on its surface after just 1 hour of use! I give it 2 stars instead of one because it bounces in the water and I want to be completely objective. Of course, despite the deep cracks in the material, you can still use it. Personally, I regret buying it. It's quite expensive for the quality and "brand name". Go figure!