An Apparatus for mixing, comprising a tumble-blender adapted to receive and tumble a container to mix the contents of the container. The apparatus includes a drive means for driving a mixer of the container. The drive means is adapted to dock with the mixer when the container is received by the tumble-blender to enable operation of the mixer by the drive means. The drive is movably mounted, relative to the tumble-blender, to facilitate docking of the drive means with the mixer.