A cooler arranged in a PCU is provided with a bottom plate, a top plate and a shell arranged between the bottom plate and the top plate. The photodetector has a detection surface greater than a light incident surface receiving light from a spectrometer. Other aspects and implementations are contemplated. Once loaded with product, the first and second top panels may be folded down to enclose the container. To achieve low and uniform wear, automatic reshaping of the sealing surfaces for advancing wear, low friction forces, and long service life, the sealing element has sealing surfaces and sealing counter surfaces, whose sealing effect is provided by the interaction of a sealing element constructed as a tractrix body with a correspondingly shaped sealing counter element.