The finest natural squirrel tail hair mixed with Risslon (a synthetic filament) which gives this brush excellent flow and added spring. Squirrel hair holds more liquid than any other natural hair and is excellent for watercolor washes. Connoisseur Risslon brushes are soft yet resilient and point beautifully. They work perfectly with any waterbased medium from ink to acrylic, watercolor and gouache. Connoisseur Fine Art brushes are guaranteed for the life of the brush against defects in materials or manufacturing.