| 摘要 |
A softball associated with the game of softball comprises a core, an inner cover and an outer cover. The core is made by a mold and of either a cork material or a polyurethane material. The inner cover surrounds said core, being made of a material different from the core and selected from the group of a cork-type material and a polyurethane-type material. The outer cover surrounds both the core and the inner cover. The softball thus formed can sustain substantially constant hardness against variations in temperature and humidity. Further, by adjusting the ratio of thickness of the core and the inner cover, the softball can attain a higher coefficient of resilience as required.
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