| 摘要 |
An inner-tube divided into many isolated cells of air. Two tubes on inside circumference of said inner-tube, one for inflating air and the other for deflating air. Each cell has two one-way valves, one for filling air and the other for extracting air. The inflating valve could have an observation window or an air pressure gauge attached to it for indicating when there is a puncture in one or more of the cells of air in the inner tube.
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