For smooth controlled brushstrokes, fine detail and line work.  Especially good for nail tips, eyebrows and painted hair. 
To Use:  Mix a small amount with paint (approximate ratio of 2 parts paint to 1 part Flow) instead of, or in addition to, minimal amounts of water. Flow Medium assists where fine line work and detail is needed without over-diluting colour or binding ability.    Using Flow Medium instead of ALL water to blend and thin paints will add to the vibrancy and longevity of the paint.  Too much water has been shown to break the pigment-binder bond, causing fading, peeling, and rubbing off of paint.  
The addition of Flow Medium may delay drying time.