Which file should I choose?
Use Allen-Bradley-1794OA8-DWG-2D-CAD-Block.dwg to insert the supplied editable drawing into your layout. The ZIP contains the unmodified Allen-Bradley-1794OA8-DWG-2D-CAD-Block.dwg.
Allen-Bradley-1794OA8-STEP-3D-CAD-Block.zip is the original NHP Electrical Engineering Products archive. Open 1794_OA8_Assy.stp inside it to place the original solid geometry in your 3D assembly.
