The Sahara 640 pens were part of Pelikan's Beauty of Nature series and were issued in 2007.  Pelikan made a fountain pen, rollerball and ballpoint, respectively the M640, R640 and K640. 

For sale here is the fountain pen, the M640 with a beautiful two-tone 18K medium nib.  The pen is brand new, and comes with original case and booklet,all in pristine condition.The outer cardboard box is also included, which has wear as shown.

I am also selling the Sahara rollerball and ballpoint pens, both brand new, in separate ads.