Since its debut in 1976 as the world's first brush pen using synthetic fibers, the long-selling "Pentel Fude Pen" has been a beloved product. This brush pen embodies Pentel's DNA. To replicate the writing feel of "weasel hair," considered the highest quality animal hair used in brush making, Pentel developed an advanced "nylon taper processing" technique that gradually tapers the tips of each nylon fiber. Furthermore, by combining fibers of different thicknesses and shapes in optimal proportions and bundling them so that all the fibers converge at the tip, a durable and well-formed brush tip is created. This allows for the supple writing experience unique to brush pens. Although it is an unused item, the outer box has some stains. I will also be listing this on other sites, so please comment before purchasing☆