Mark-it Retractable Permanent MarkerConvenient, easy-click retractable permanent marker is perfect for marking on the go. Marks on just about everything including glass, metal, plastics, photos, foils, coated papers, and oily and damp surfaces. Seal Guard Defends Against Dry Out™. Durable fine point for precise marking. Acid-free ink (no added acid; no measureable pH.) Marker Type: Permanent; Color(s): Blue.