These UV blacklight reactive invisible ultraviolet markers by DirectGlow use our specially formulated high quality water based invisible ink blend for the best blacklight effects! Perfect for secret messages, marking merchandise, and other stealthy security uses. Colors glow an incredibly bright in blacklight. The ink adheres to any porous surface with ease and dries fast. Virtually invisible and won't wash off easily like other brands. Fine tip allows for precision application. 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. Ink safe for general use on the hands and skin. Avoid sensitive areas like eyes and mouth. Marker is non refillable.