A fountain pen — a pen that uses liquid ink and is refillable; often preferred for formal writing or signatures.
祖父に万年筆をプレゼントしてもらい、大切に使っている。
My grandfather gave me a fountain pen as a gift, and I treasure it.
インクが切れたので、万年筆に新しいカートリッジを入れた。
The ink ran out, so I put a new cartridge in the fountain pen.
万年筆で手紙を書くと、字に味が出ると言われる。
They say handwriting written with a fountain pen has character.