The ink from the pen is etch-resistant so you have a quick and simple way of making a PCB! Being waterproof it is also great for labeling things on or about the boat, caravan or motorhome. The ink will wash off afterwards with metho, turps, etc. • Excellent smudge-proof and waterproof qualities • Dries in seconds • Low-odour ink • Xylene and toluene-free ink • Line width fine approx. 0.6 mm • Blue