Fountain Pen
noun
The only kind of writing brush you can use for ten thousand years is a fountain pen! All other pens run out of ink and then you're out of luck. But fountain pens can be refilled, making them work for pretty much exactly ten thousand years.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
万年筆を落とされましたよ。
You dropped your fountain pen.