This UV blacklight reactive invisible blue large tip marker uses our high quality water based invisible ink blend. Perfect for secret messages, marking merchandise, and other stealthy security uses. Glows an incredible bright blue in blacklight. Ideal for metal, glass, plastics or paper. Can also be used on aluminum, ABS, acrylic, rubber, cellulose, acetate, formica, nylon, polystyrene and polyethylene. Totally invisible and wont wash off easily. Large tip is ideal for covering larger areas with minimum passes. Marker comes ready to use and is formulated to fluoresce brightly under long wave ultraviolet or LED blacklight. Ink is non-toxic, fast-drying and non-transferable. Ideal for applying onto an already printed surface. Marker is non refillable.