Reducing socket for receptacle carriers of laboratory centrifuges for accommodations of test tubes or test vessels

The reducing socket which is constructed as a cage, is essentially formed by six walls, which are joined together in a cube-shaped or parallelepiped-shaped manner. These walls are provided with openings for the insertion of test vessels. The burrholes of the individual walls are of different sizes. These openings on an individual wall may have both equal and different sizes. The supporting plate which is attached either within or outside of the cage, covers the openings of this wall, which is situated opposite to the wall accommodating the test vessels. If the supporting plate lies within the cage and the size of the test vessel is changed, this plate falls by itself to the wall, the openings of which are covered-up. The reducing socket according to the invention enables the use of different test vessel diameters, without requiring a particular expenditure.