Tombow Dual Brush Marker Set 10 Pack - Grey Scale. Each pen has a flexible brush tip and a fine tip in one marker. Brush tip works like a paintbrush to create fine, medium or bold strokes; fine tip gives consistent lines. The water-based ink is bendable and the resilient nylon brush retains it's point stroke after stroke. The tips are self-clean after blending. Acid-free and odourless.