Reflection probe

Measuring apparatus in the form of a reflection probe, comprising a measurement position in the form of a window in a window surface and a cleaning device in the form of a flushing nozzle in a front surface, characterized in that the window is integrated in a planar fashion into the window surface, which is inclined at an angle of from 10° to 25° relative to the front surface of the measuring apparatus, the flushing nozzle being integrated into the front surface which is reduced by the proportion of the window surface, and the outlet opening of the flushing nozzle being located adjacent to the window surface in the front surface.