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Paragraph Number

13

The opening may have an elliptical cross-section that may have a height that is smaller than a width of the elliptical cross-section. The first mesh and the second mesh may each have a first pattern. The first pattern and the height of the elliptical cross-section of the opening may each be selected such that activation of the driver of the expansion mechanism causes a predetermined increase in distance, a predetermined spacing, between the upper plate and the lower plate.

Added by DJM 2 2021