That is to say, the difference between nylon and animal hair oil paintbrushes. Nylon pens are cleaner and cleaner than animal hair. Although they can also be connected freely, they will inevitably have a blunt feeling sometimes, while animal hair brushes You can be more comfortable with the brush strokes, soft and hard virtual and real will be more natural. But the nylon pen should be washed in time. It cannot be soaked in the pen holder like a brush made of wool. It will be deformed after a long time. It is best to wash the pen in time. It will not be easy to use after a long time.