FeaturesIncludes a UV lightChecks authenticity of banknotesShows clear or light amber if note is genuineShows brown or black if note is counterfeitWorks on old paper notes and new polymer notesDetect counterfeit notes in seconds with this 2-in-1 Securikey Counterfeit Detector Pen with UV Light. It includes a UV light that can highlight the hidden authenticity markers on banknotes. If nothing appears under the UV light, you can mark the note with a pen. If the ink dries clear or a light colour, the note is genuine, or if it dries with a dark mark, the note is suspect.