| 摘要 |
<p>A conduit includes a multilayer wall including an outer layer having a first color; an intermediate layer having a second color; and an inner layer having a third color, wherein the intermediate layer is between the outer layer and the inner layer, and the first color, the second color, and the third color are different. Each of the first color, the second color, and the third color indicates a level of wear of the multilayer wall when one of the first color, the second color, or the third color is exposed due to wear or abrasion. 3421155_ (GHMatters) P90635.AU 6/06/12 (Y)J</p> |
