The invisible ink contains special high brightness ultraviolet viewable compounds. The ink is completely invisible in normal light. The secret messages can only be revealed by the beam of the UV Blacklight. This beam consists of ultraviolet energy close to the visible spectrum of light which causes particles within the ink to fluoresce illuminating the message.
Not suitable for children under 3 years of age.
Invisible ink is non toxic but permanent.
Measures: 5.75"L x .25"W x .25"H