Squirrel hair. Long, flat, dagger shape. High quality Japanese brush. Comes to a needle point when wet, holding an immense amount of moisture. Striping and lining brush for watercolour and ink. Also used with clear lacquers as touch-up brush. Excellent detail brush. Short handle.
Approx size of bristle
Size 0 this one is 7mm across the ferrel & hair 42mm at its longest
Size 1 this one is 8mm across the ferrel & hair 45mm at its longest
Size 2 this one is 9mm across the ferrel & hair 47mm at its longest
Size 3 this one is 11mm across the ferrel & hair 53mm at its longest
Size 4 this one is 13mm across the ferrel & hair 60mm at its longest