From Amazon
edding 750 Paint Marker - Blue - 1 Pen - Round Tip 2-4 mm - Paint Marker for Marking and Labelling Metal, Glass, Rocks or Plastic - Heat-Resistant, Permanent, Smudge-Proof and Waterproof
Conrad Electronic
Edding 750 paint marker 4-750003 Paint marker Blue 2 mm, 4 mm