... invisible light, can detect multi currency with Sound control Infrared(IR) Anti-Counterfeit Detctor Model : HT1 1,Detecting Theory Based on ... with infrared Anti-counterfeit material. 2,Application methoTo aim the detector head at the item, to press the swith continuously,when ... work, no voice . If the item include moreInfrared material , the detector can work only at distance of 2cm. even the item ...