The five pen set is perfect for sketching, drawing, illustration, journaling and more. Pigmented, water based ink is acid free, fade proof and water proof. Set includes: .05,0.1,0.3,0.5 and a brush tip. Conforms to ASTM D-4236. Pair this set up with your favorite Pentalic hardbound sketchbook, Traveler Journal or Illustrator sketchbook for the perfect Urban Sketch set.