Helvetica Narrow is another popular font from the Helvetica family. This type of typerface beholds characteristics that hold between the appeal of Helvetica Compressed and Helvetica Condensed. The difference is clearly visible in the width that is scaled in an optically consistent manner in alignment with the fonts having widest width.
The font was basically introduced to compensate for the limited printer ROM space. To ensure this limitation, the standard font was mathematically distorted to thin verticals and thick horizontals. It was a blessing then, but it still retains its value today.