The Birchwood Casey Industrial Touch-Up Pen is a specially formulated, super permanent ink that you can use on nearly all materials, metals, plastic, textiles… as a touch-up or permanent marker. For blued steel and black anodized aluminum, the industrial formula remains permanent against most solvent/chemical washes. Also resists bleeding and fading when exposed to light, steam and heat (up to 500° F). Excellent black color match for nearly all touch-up applications; for both gloss and matte situations for shooting and hunting enthusiasts. The Universal Touch-up Pen is an excellent product for most touch-up and marking applications.