The NibStretch property returns or specifies the thickness of the Brush tool in a calligraphic outline. Values range from 1 to 100, and the default value is 100.
Examples:
The following VBA example assigns a very thin horizontal pen nib to the outline of the active shape.
Sub Test()
ActiveShape.Outline.NibAngle = 90
ActiveShape.Outline.NibStretch = 1
End Sub