FRH-B - Broad brush. FRH-M - Medium brush. FRH-F - Fine brush. The Aquash Brush is a refillable multipurpose brush that can be filled with water to blend watercolours or with coloured inks and water soluble paints to create watercolour effects. Features a flexible nylon brush tip which will not fray like hair brushes. The tip has been specially treated to absorb and hold the ink for longer lasting strokes.