Dual brush pens have a versatile, flexible nylon fiber brush tip on one end and a fine tip on the other end. The resilient nylon brush retains its point. Water-based, non-bleeding ink is blendable. Set includes one dual-tip colorless blender plus nine primary colors: black, brown, crimson, cyan, deep blue, process yellow, sap green, scarlet and sea green. Acid-free. AP Seal, non-toxic.