Among hairs from weasels' tail, under jaw,  and fore breast, which are widely used to produce wolf hair brushes, the tail parts are the best and usually for the high end product. Some low price wolf hair brushes are made from mount horse hairs, please read the retail. 
Wolf brushes are relative stiff. 
Some suggestion but not the definition depending on each user's habit and skills
Painting: Good for  Calligraphy and signature for painting, Bamboo, orchid, petals and strokes. Small/script size can be used for ribs of a leaf.
Branch in the method of double sketch/ bone style, such as plum tree. (雙鉤法畫梅幹）.Bill of bird. Stone, mountain, sketch in landscape.
Calligraphy: Good for Regular Script, Official Script 楷書，隸書

Wolf Hairs and other Hard Hairs

2pc- 24pieces Wolf Hair Brush Chinese Calligraphy Painting Ink Sumi B024
$7.49 - $12.99
$7.49 - $12.99
XL Badger Hairs 石獾 Brush Premium Calligraphy Painting Chinese Sumi-e Produce B025
$41.99
$41.99
1 Piece Mixed Hairs Red Hairs Bamboo Shaft Brush Fine Line Script Detail Sumi e B020
$7.49
$7.49
Weasel Tail Hairs Rosewood Shaft Premium Brush B026
$27.99 - $83.99
$27.99 - $83.99
No.1 Brand Shuangyang 雙羊 Wolf Hairs Brush B028
$16.99 - $38.99
$16.99 - $38.99
Rabbit Hair Chinese Hard Hairs Brush B029
$9.29 - $25.99
$9.29 - $25.99
Bear Hair Brush Professional Calligraphy Painting Chinese Sumi-e Produce B030
$23.99
$23.99
Wolf Weasel Horse Hair Brush Wood Shaft Calligraphy Painting Sumi-e Chinese Japanese B031
$12.69 - $33.99
$12.69 - $33.99
Weasel Tail Hairs Carved Solid Woods Shaft Brush Set /w Gift Box B032
$23.99 - $73.99
$23.99 - $73.99

On Sale

On Sale

Sumi-e Calligraphy Painting Brush Badger Hair Wood Shaft B033
$14.99 - $86.99
$9.99 - $86.99

On Sale

On Sale

Various Hairs Ebony Shaft Grape Eyeball Peony Brush B034
$22.99 - $72.99
$22.99 - $69.99
1pc XL Brush Jing Zha Wood Shaft Chinese Japanese Calligraphy Sumi-e B019
$32.99
$32.99
No.1 Brand Shuangyang 雙羊 Fine Line Script Rabbit Goat Mixed Hairs Brush B010
$17.49
$17.49

Sold out

Sable Hair Chinese Hard Brush Bamboo Shaft B035
$20.50 - $62.99
$20.50 - $62.99
3 Piece Set Weasel Hairs Brush Sumi e Red Star Brand Shuan Brushes B036
$85.99
$85.99
Weasel Hair Brush Wood Shaft Calligraphy Painting Sumi-e Chinese Japanese B039
$12.49 - $33.99
$12.49 - $33.99
Wolf Weasel Hair Brush Detail Outline Script Gong Bi Sumi-e Painting Calligraphy B041
$6.89 - $19.99
$6.89 - $19.99
One Piece Wooden Brush Gift Box
$15.99
$15.99
One Piece Brush Gift Box
$6.99
$6.99