| 摘要 |
An exercise balance trainer includes a hard board and a resilient ball body connected to the board. The ball body has a first curved wall with a first rim, a second curved wall with a second rim connected fixedly to the first rim so as to define an air-receiving chamber between the first and second curved walls, and an annular flange connected to the board and a junction of the first and second rims. The first and second rims have the same diameter. The first curved wall has a maximum height that is not greater than one-half of the diameter of the first rim. The second curved wall has a maximum height that is not greater than one-third of the diameter of the second rim.
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