Helix rod for MB 146/149

Manufactured from black Delrin plastic, this rod has a circular cross section which is a much stronger alternative to the original oval cross section

Please follow the links below for a comprehensive description of this part from a renowned repairer of M.B pens. I think they are quite interesting.

http://www.fountainpennetwork.com/forum/index.php/topic/255063-modern-montblancs-weak-piston-lead-screw/

http://www.fountainpennetwork.com/forum/topic/276873-another-d-i-y-149-repair-pictorial/