US Patent 7201672 Multi-piece solid golf ball

A multi-piece solid golf ball comprising a solid core and a cover of two inner and outer layers surrounding the core. The outer cover layer has a surface formed with a plurality of three types of dimples such that a product of the Shore D hardness of the inner cover layer multiplied by the Shore D hardness of the outer cover layer and a proportion VR (%) of the total of the volumes of dimple spaces satisfy one of:(1) 1,500 to less than 2,000VR: 0.8 to 1.1%(2) 2,000 to less than 2,500VR: 0.75 to 1.05%(3) 2,500 to less than 3,000VR: 0.7 to 1%(4) 3,000 to less than 3,500VR: 0.65 to 0.95%(5) 3,500 to 4,000VR: 0.6 to 0.9%.