Measuring device for determinine module structure with property of gas to be measured

The invention relates to a measuring device for determining a module structure with a property of a gas to be measured and to a method for producing the measuring device. The measuring device has an electronic module having a radiation source for emitting radiation and a detector unit for at least partially receiving the emitted radiation after the radiation has passed through a measuring space; the measuring device has a housing which is connected to an optical unit for at least partially shaping and/or guiding the radiation emitted by the radiation source. The described technical solution is characterized in that the optical unit has at least one reflector which is produced as an off-axis reflector with respect to the main beam axis of the radiation, and the electronic module and/or the housing has at least one fastening means which is designed such that the electronic module and the housing can be connected to each other without tools in a position in which the electronic module and the housing are aligned