Individual nib units for the Pelikan M625 and M640 are easily interchangeable and well suited for customization. The single-tone, fully rhodium-plated 18k gold nib is available in widths M, B, OB, and BB. Widths EF and F have sold out and are no longer available from Pelikan. The M625 nib unit is the exact same size as the M600 and M605 nibs, the difference being the M625 nib is made from 18k gold while the M600 and M605 nibs are made from 14k gold. The M625 nib can fit into the M200 and M400 sized pens as long as the nib is set deeper into the collar to prevent it from hitting the bottom of the cap. We can perform this service free of charge, just add a note to your order indicating the nib will be used in a M200/400 size pen.