The open geometry of the single-sided NMR-MOUSE® sensor results in a powerful spectrometer to characterize arbitrarily sized samples. This inhomogeneous magnet is designed in such a way that it generates a highly flat sensitive slice, i.e. the measurement volume, at a given distance (25 mm for the PM25 system) parallel to the scanner surface [1]. It is well known that low field magnets have a strong dependence between the magnetic field and the magnet temperature. For the NMR-MOUSE® it leads to a dependence Materials between the magnet temperature and the position of the sensitive volume [2]. As our aim is to use this portable device under unstabilized temperature conditions, we anticipate variations in the measurement position. This study aimed at characterizing the relationship between changes in the magnet temperature and the position of the measurement volume. Measurements were performed at two sites with two different PM25 NMR-MOUSE® spectrometers.