Sharpie T.E.C. Marker marks on most surfaces and meets requirements for trace element certified ink for the nuclear energy, aerospace, electronics, aeronautic and ship building industries. Chloride and other halogens cause stress corrosion on metals and should not be used on stainless steel or titanium. Fine-tip permanent marker is trace element certified. Design also features a cap to protect the ink and a pocket clip for attaching the marker to notebooks, pockets and more.