Which file should I choose?
Use ntsxtb02030h_2D-front.dxf (revision 1.0) to insert the supplied editable drawing into your layout.
Use NTSXTB02230H_simplified.stp (revision 1.0) to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified NTSXTB02230H_simplified.stp.
