So, I finally got my hands on a vintage Esterbrook lever fill fountain pen! It needs a new sac and from what I can tell it needs a #16 size sac. This will be the first fountain pen I will attempt to clean and re-sac myself. I do not plan on restoring any number of pens and in an attempt to keep costs down, I am only looking to purchase one sac. Do any of you gentlemen know any companies or sites that sell single replacement sacs not in multi-packs. I am trying to avoid paying for a pack of 5 or more just to use one. Any help is much appreciated, as always! Thanks!