Refillable water tank brush is a practical utensil for watercolor techniques, especially in combination with water-based brush pens such as ABT Dual Brush Pen.
3 different brush tips available. 
The fillable water tank brush is a practical utensil for watercolor techniques. The water flow is regulated by pressure on the shaft. The water tank brush with protective cap is ideal for on the go. Suitable for working with the ABT Dual Brush Pens and other water-soluble paints. For watercolor, watercolor, lettering, illustrations, urban sketching, manga and much more. The water tank brush is delivered empty and is easy to fill and refill by screwing on the tank. The tip is easy to clean with water.
 
(Photo source: Tombow)