I just bought an Osmiroid 65 Lettering Set for Left-handers on eBay. Copyright date is 1974. The set comes with six assorted nibs. This is my first lever pen. My questions are: Do I need a separate sac for each nib? There did not appear to be a sac in the barrel of the pen, but I can't really see anything in the barrel. Some flakes came out of the barrel when I pounded it (gently!) in the palm of my hand, but I don't know if that was dried ink or sac flakes. Second question: Where exactly is this sac attached? Does the shellac go between the sac and the nib unit, or above the sac or over the sac? Some of the nib units have the sizes of the nibs on the lower part in white ink. I would think that that is where the sacs attach, but I was surprised that the size lettering was in such good shape. I can't tell if a sac was ever attached to them, except for one or two units that had ink in them when I cleaned them. My main concern is the ease and ability of going from one nib to another. I also have a more modern (relatively speaking--from the late 1970s) Osmiroid Calligraphy set with a set of nibs that take cartridges. I've used it for 30+ years and have always enjoyed it, so thought I'd give the 65 a try. On another random tangent, I don't find much about Osmiroid on the internet, not in comparison to all of the Shaeffer/Pelikons/Pilot/etc posts. Is it just a junk pen? (I still like writing with it...) Thanks, John