I have for sale from my collection a very wonderful and early Montblanc 149 Silver Rings. It has an extended ink window. The star of the show on this pen is its L139 14C OB nib. Those familiar with these early pens know that after the MB 139 was discontinued they had nibs left over which were fitted on the early 149 pens. This is such a pen and is identified by the cross hatching surrounding the M on the Nib. The nib is an oblique broad and an exquisite writer. OB is marked on the turning knob as is 149.
The pen which has a two stage metal piston mechanism was serviced for me by Osman Sumer two summers ago so is in excellent working and cosmetic condition. There are two minor negatives of the pen. One is that the original feed was replaced by a 1970s service feed long before I acquired the pen. It is such a wonderful writer that I have not considered replacing the feed to a period correct one. Second is that the bottom ring which is tight to the Meisterstruck ring can be loosened by moving it with ones fingernail. It moves only a millimeter or so and is not going anywhere but it is a nearly 75 year old pen so its not perfect but pretty close.
Asking $2700US shipped in Canada and the USA

Here are some pictures please excuse the dust spots: