| 摘要 |
<p>The horseshoe-shaped base (1) is provided with several vertically positioned guiding elements (2) along the inner surface of its outer border. The elements (2) are of different heights (3) as required. A vertical partition (4) is located between the border and the exchangeable inner element, which is provided with a threaded central bore (5). Split-casts (6) can be positioned at the lower surface.</p> |
