Hmm… Is this signature really authentic? Can ink be analyzed? With this Die drei ??? set, forgeries can be uncovered and secret messages can be written. It includes a holder for chromatography experiments and a special brush with an integrated water tank. Making your own invisible ink? No problem at all. Secure evidence like real detectives – a cool role-playing game for children aged eight and up. The detective set is always on hand in the handy metal case.