Which file should I choose?
Use NSYMR76_2D-front.dxf (revision V1) to insert the supplied editable drawing into your layout. The ZIP contains the unmodified NSYMR76_2D-front.dxf.
Use NSYMR76_3D-Simplified.stp (revision V1) to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified NSYMR76_3D-Simplified.stp.
