The smaller of my two White Tortoiseshell pens, the M400 is a good size for the pocket. I do love the honey gold tortoise body and and I am over my fear of staining the white grip and cap.
This 0.6mm Stub, custom ground by Richard Binder is probably the least exciting of my Binder nibs. The line variation of the stub is nowhere near as apparent as my italics. However it is a very pleasant and smooth writing nib.
Sadly this lovely light green ink is no longer for sale. It was discontinued several months ago but is possible to get through the second hand market. It is a great shading ink even from this relatively fine stub. I find it a very happy shade of ink that I look forward to using at the office.