The present invention relates to an apparatus (100) for producing a driving force for stirring samples, in particular samples for laboratory operations such as, for example, liquids, liquids with solid samples contained therein or solid samples, said apparatus comprising a sample holder (200) for receiving at least one sample vessel (220) for samples and a bar element (300), which extends along a longitudinal axis (LA) and which is connected to the sample holder (200), wherein the bar element (300) comprises a coupling portion (310) for detachably coupling the bar element (300) to an operating unit (800), a fastening portion (320) for fastening the sample holder (200) to the bar element (300) and for positioning the sample holder (200) along the longitudinal axis (LA) in defined fashion, and a magnetic stirring portion (330), wherein the bar element (300) is embodied in such a way that a magnetic field that rotates relative to the sample holder (200) about the longitudinal axis (LA) can be produced by means of the magnetic stirring portion (330). The invention further relates to system (700) comprising an operating unit (800) and the apparatus (100) according to the invention, which are detachably coupled by way of the coupling portion (310). The invention further relates to a process for stirring samples in sample vessels by means of the system (700).