圆头圆脑小东西,没骨头没肉光有皮,一打跳得三尺高,肚里憋着一包气。(猜一体育器材)

圆头圆脑小东西,没骨头没肉光有皮,一打跳得三尺高,肚里憋着一包气。(猜一体育器材)

揭示谜底