| 摘要 |
A Bocce ball includes, sequentially from outside to inside, a body layer, a medium layer, and a core layer. The body layer and the medium layer are made of different materials. For example, the body layer is made of unsaturated polyester resin, while the medium material is made of acrylic material. The body layer and the medium layer are securely combined with each other. The core layer is made heavy and is enclosed by the medium layer.
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