Hi to all!
I am writing on a new chapter about fountain pens. The particular topic is about the technical side of the ink reservoir. For most styles I have found all the information I need but not for the piston and bladder converter. The dimensions I would need are their volumes, the height/length to which they fill up and the mechanical length of the volume, which would be a smidgen longer.
Sure, I could buy one each. However, so far, I have always received your help, otherwise, adding it all up, it would have been quite costly.