Container to be used for preparing a multi-layered blood product by centrifugation, said container comprising a substantially cylindrical body (2) with a closed bottom (3) and a top (4) having a filling opening as well as a filter device (15), which is slidable inside the container (1). The filing opening is closed by means of a penetrable membrane (13), and the filter device (15) comprises a substantially planar mesh (16) and a supporting buoyancy body (18). In addition to this, there are means (35, 36, 39, 40, 42), for releasable fixation of the filter device (15) adjacent to the bottom (3) of the container (1).