Big Kids Choice Aqua-Flo Brush Set. These brushes work like markers! Perfect for use with watercolor books and pan watercolor sets. Fill the barrel with water and gently squeeze to start the flow. The barrel is made of durable yet easy to squeeze plastic with Taklon bristles. This package contains three: one each: small, medium and large. WARNING: Choking Hazard-small parts. Not for children under 3 years.