These Synthelux Spalter Brushes are from Italian fabricator, and are made of very high quality fine synthetic bristles.
These Spalter Brushes are an excellent choice for the application of fine finishes - the silky synthetic bristles provide a smooth, even finish, with minimal brush strokes. 
This is one of the most commonly used brushes in faux finishing, and is particularly well-suited for softening glazes and stains, as well as creating subtle strié effects.