Shanghai Crafts Small Brush Set of 4 High-quality weasel hair small brushes with excellent writing quality Weasel hair is also called yūmō (鼬毛) in Japanese. It has excellent properties such as cohesion, elasticity, and sharpness. Because it is durable and the tips of the hairs are not easily worn down, it is used for small brushes for fine writing and kaisho (block letters). I liked them and bought a set before. I hope you will find them useful. Thank you for looking.