Before selecting a specific system application, the user interface appears neutral (logo, etc.). The handpiece is not connected to the system, the LED light band is deactivated. After activating the desired application field, the menu navigation of the user interface is colour-coded to provide an intuitive control to avoid operating errors. Each application receives its own unique colour code. This code is transferred to a handpiece after it has been connected to it. The disposable products, such as probe and REF cap, are colour-coded and must be purchased as required. The main element of the system is the handpiece. It contains all necessary electrical components such as the spectrometer, controller and the LED light source. The handpiece works wirelessly and is connected to a display medium (e.g. Tablet) via WLAN or Bluetooth. The calculation process, which converts the detected spectra into the NIRS value, takes place on the calculation unit (controller) of the handpiece so that in addition to the control (triggering), only the already calculated value needs to be transmitted.