A magical felt tip pen that uses invisible ink that appears in the beam of the UV torch hidden in the lid. The design features an on/off buttonand functions with 3 LR44 HD batteries (included).\nChildren will love writing secret messages to each other or using them to write in their personal journals.\nPlease note this product contains button batteries (within the pen that are unremovable and can not be replaced). Button batteries are unsafe if swallowed.\nSuitable for ages: 3+ years