| 摘要 |
<p>A helical formation (2) for a conduit (1). The helical formation (2) comprises an elongate member defining at least a portion of a helix, the elongate member comprising two inwardly extending portions (6, 7). The inwardly extending portions (6, 7) are spaced from each other and extend along the length of the elongate member in side-by-side relationship.</p> |
