Dark marking on stainless steel, laser metal engraving - manufacturers of Laser fiber marking technology
All you need to know about metal engraving / etching / marking - EnduranceLasers
Amazon.com: OMTech Laser Marking Spray, Metal Laser Marking Fluid for CO2 Laser Engravers, 13oz Aerosol High Contrast Black Spray for Laser Engraving Metal, Laser Ink Agent for Aluminum Stainless Steel Brass More