It comes from https://www.fountainpennetwork.com/forum/index.php/topic/257502-parker-vacumatic-maxima/ ... by association of ideas. Taking advantage in these part of the year own for gifts, herewith a scheme made by me that I want hopefully help to someone FPN user. In any case it is useful to call each Vacumatic by his real name according with the year in which it was manufactured. It is also very funny how you can date the Vacs. according to the imprint MADE IN USA -I think it might be the first time we talk about it publicly, I do not know- as MADE IN USA PAT, USA left or USA centered both without PAT). Or dated by the varying width of the bottom of the "feathers" on clip. Really funny. click here for higher photo resolution VACUMATIC SCHEME (if anyone have upload capacity to incorporate the scheme with higher resolution (photo linked) to this thread, you can, thanks)