The device has a testing element (41) received on a receiving surface (20) of the device, where the receiving surface is provided on a narrow side or a section of the narrow side of a housing (1). The narrow side or section of the narrow side of the housing is raised in relation to adjacent components of the device and/or provided with an exposed layer. A housing part is angled on the receiving surface at an angle of 30 to 70 degrees, and a plane is mounted perpendicular to a machine plane through the receiving surface or relative to a vertical arrangement around an angle of 20 to 70 degrees.
