IPen.Width
IPen

property Width: Integer;

Type Library
TeeChartx

Description
The Width property determines the width of lines the pen draws.

Warning:

When drawing to Screen, the Width is expressed in pixels. When drawing to Printer or to Metafile canvases, the Pen Width will be converted based on TChart.Detail property.

Windows GDI has a special Width value of "0", that corresponds to the minimum pen width the drawing device supports.