The Corners pane determines the size of the corners on the dial on your Radial gauge.
Extent — Set this value to an integer from 0 to 999. If you set the start and end angles on the Angle and Extents pane to sweep fewer than 360 degrees or change the shape of the dial to a rectangle on the Shape pane, you can see the effect of the extent value. It determines the roundness of the visible corners.
Spline Tension — Set this value to a value from 0.0 to 1.0. This value determines the curviness of the corners of the dial.