The noncontact double sheet detector system I20 is based on the transmission principle with transmitter and receiver and is especially well suited for pass-through double sheet detection. The I20 system has been recently completely redesigned and enhanced and is suitable for both belt conveyors as well as magnetic conveyors. The sheet thickness range for steel is up to 8,00 mm single sheet thickness. For less demanding application is the lower cost I100 with teach-in facilities available.