An agitator 100 comprising a rotatable impeller 101 comprising blades 110, magnets 150, and a shaft, wherein the impeller is configured to be driven by a drive unit magnetically coupled to the impeller, and an impeller seat 200 receiving the rotatable impeller, the impeller seat comprising an upwardly arranged cylindrical housing 205, a flange 210, and a base 220, the cylindrical housing comprising a central opening 260 for the impeller shaft, and the base comprising a collar 225 and pins 230 arranged to engage with a locking and centering mechanism, as well as a mixer engagement unit including the agitator, a mixer system, a mixing vessel, and methods of using the agitator, mixer engagement unit, mixer system, and mixing vessel, are disclosed.
