Which file should I choose?
Use NVENT-PFS1100316-2D-CAD-Block.dxf to insert the supplied editable drawing into your layout.
Use nVent-HOFFMAN-PFS1100316-3D-CAD-Block.stp to place the original solid geometry in your 3D assembly. The ZIP contains the unmodified nVent-HOFFMAN-PFS1100316-3D-CAD-Block.stp.
