Does anyone know how may types available.

Very nice collection. I have a few of them as well. I also agree that the Pilot custom is one of the nicest designs out there. As to how many variations are out there, i think a lot, but i leave the answer to Stan. He will probably have a rough idea and certainly a few pictures of his Pilot custom pens to share.

Nikolaos

My guess is about 25 to 30 models exist. This includes the various makie designs and designs custom made for associations, religious groups, businesses, etc. Below are pictures of some of my Custom. There are seventeen in my collection and I have not made an effort to obtain any of the makie models. Two are custom designs and not part of their regular line-up.

Tofurther complicate this question, when Pilot introduced the line in 1972 (I've not seen any nibs dated earlier. At least as best I recall at 4 in the morning) they used their standard inlaid nib too. This was short-lived and, if you find any without the big inlaid nib, it is not a frankenpen. They can that way.

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Click to view attachment

Thank you Stan
Your customs are beautiful.
Hope I can get more customs in the future.

that looks so nice, i love them too, especially the ones with the buddha sutra, heart sutra