PenTouch® metallic and white inks lay down opaque marks on most papers and non-porous surfaces. Ideal for finer marks on steel & iron, sheet metal, glass & plexi-glass, wood, ceramics & porcelain, and plastics. Industrial applications of these valve-action paint markers includes: marking and identifying parts, pipes & tubing, sheet metal, wiring, construction assembly, manufacturing & fabrication processes. PenTouch adheres permanently to most surfaces and is low-odor.