Which file should I choose?
Use xesb2011-3dCAD_2D-front.DXF (revision 1.0) to insert the supplied editable drawing into your layout.
Use xenb1181-3dCAD.stp (revision 1.0) to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified xenb1181-3dCAD.stp.
