Each Tombow Dual Brush Pen has two tips: a fine one that's perfect for details and a flexible brush. The brush is durable yet soft, and you can easily use it to create fine, medium or broad strokes. Its also ideal when you want to fill larger areas with colour. The ink inside the pens won't bleed, and is odourless and acid-free. Colours are not light resistant. Since it's water-based, you can blend the colours, just as you would with watercolour paint. Tombow Dual Brush Pens are particularly popular with graphic artists and watercolourists, and are ideal for all arts and crafts, illustration, typography, manga drawings, card-making, rubber stamping, scrapbooking, calligraphy and more.