Dear FPN, I am trying to learn more about this pen stamped Koshin. It is a Japanese eyedropper with sealing rod. The barrel is marked: Koshin / Made in Japan. The nib is marked: Warranted / Hardest / Iridium / <1> / Special / Pen. Interestlingly the section on this pen is in two pieces. Any information on this mystery pen would be appreciated. Pen_Padawan