This pen is made of the hair on the tail of a weasel. The rat tail produced in Northeast China is the most common, and it is called "North Langhao" and "Guandong Liao Wei". Wolf hair is stronger than wool pen and suitable for writing and drawing, but it is not as durable as wool pen and more expensive. Common varieties are Zhu Lan, freehand brushwork, landscape, flowers, Ye Jin, costume patterns, red beans, small seiko, deer and wolf hair calligraphy and painting (made of wolf hair and deer hair), leopard and wolf hair (made of wolf hair and leopard hair), special long-peak wolf hair, super long-peak wolf hair and so on.
Writing regular script such as running script or cursive script with wolf hair is very enjoyable, and writing official script or Yan Kai's regular script with sheep hair full.
Yang Hao's pen is soft, but it absorbs water very well.
Langhao absorbs a lot of water and is hard.
Look at personal preference when using it. Personally, I feel that it is better for beginners to use wolf hair.
I hope my answer is helpful to you!