| 摘要 |
An exercise ball has a bladder, a yarn lining wound on an outer face of the bladder, an air layer formed between the outer face of the bladder and the yarn lining, a cloth lining wrapped on the yarn lining, an adhesive layer applied on an outer surface of the cloth lining, a sponge lining securely attached to the cloth lining by the adhesive layer, and an outer surface securely engaged with the sponge lining. With the provision of the air lining and the sponge lining, the exercise ball is able to maintain its softness.
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