Hollow Ball is made of polypropylene (PVC) plastic synthesized from two sides of a spherical, each hemisphere on twelve half the fan blade, the two hemispheres of the fan blade staggered. The specific surface area is big, it is characterized with high void fraction. But because the leaf number, the more the shading effects between each other, is not conducive to the liquid distribution and wetting. Most liquid in sphere hollow column, hinder the gas flow, thus resistance is bigger. This kind of packing used in water treatment engineering.