The uni-ball PIN is an excellent artists pen. The ink is water resistant too so the drawing pens can be used with watercolour and will not smudge when wet. The 0.1 nib creates strong, slender line, the 0.2 and 0.3 nibs make clear, precise marks while the robust 0.5 tip is ideal for definitions and the 0.8 is excellent for heavy outlines and colour blocking.
eBay