evaluation device for reliable double-sheet testing of ferrous or non-ferrous metal sheets (single-side contact and non-contact measurements, and double-side non-contact measurements). The system consists of an evaluation device (BDK-1.3) and two more sensors. Additional sensors can be operated by a T-coupler or sensor switch. Simple and extensive programming of program memory for up to 256 different materials and thicknesses using associated sheet metal thickness sensors. Interfaces with system controls, various standard fieldbuses, and download and upload program parameters. Robust and proven design has numerous applications in the automotive industry.