The Tombow Water Brush is an ideal companion for the Tombow Dual Brush Pens. Easily blend water-based markers, watercolor paint, pencils or crayons with the soft, flexible brush tip. Fill with water to blend or add ink or dye. Gently squeeze barrel to apply. Use the Small and Medium Water Brush for fine details, and the Flat Brush for broader coverage. Available in Small, Medium, and Flat brush tips. Fills up to 5.5ml.