A laboratory assembly holds a test tube while the contents are mixed or moved by a magnetic drive. The test tube (26) is held in a rack with an upper and lower deck. The spinning test tube is supported near the top by a hole (24) in the rack top deck, and at the bottom by a Y-shaped rest (27) whose lower part has a pivot-recess and incorporates a magnet (29). The base (27) pivot-recess section of the Y-shaped support projects through a lower deck (2) hole (12) in the test-tube rack. The base (27) pivot-recess section is located immediately alongside adjacent spinning magnets (11). The magnetic drive unit stands (3) on a base plate (1) with an upward-directed conical pivot (22), or has a recess for a pencil-like pivot extending downwards from the base (27).
