Hi, Harvey. Here is another article on the Pen. I've ordered one as the result of your interest. I, in general, am very happy with the Montblanc line. Other than one which I purchased and appears to be a fake, they are all great pens. There is a certain amount of division on this pen in particular as it doesn't take other than cartridges without a converter, the cap doesn't post, and it may not take a standard converter (smaller might work). Here's a second an third article on the pen (at least one of its variants).
https://www.gentlemanstationer.com/b...k-fountain-pen
https://ukfountainpens.com/2019/11/0...ht-experiment/