HAMMOND PRO was developed by Nittaku under the brand-new idea "Integrated Energy (IE)" This technology applies a newly developed way of mixing natural-rubber and synthetic-rubber. The results of the latest Japanese production methods are: (1) The natural-rubber ingredient grabs a ball firmly; (2) At the next moment, the synthetic-rubber ingredient shoots the ball like a bullet. (Refer to the sketch) In addition, this hard sponge chosen by the super top player is suitable for the powerful attacking.