A rotatable rotor for separating components contained in a fluid,
comprising an annular base having a first annular channel and an annular
cover having a second annular channel for holding a flexible
doughnut-shaped centrifuge bag therebetween. The cover has one or more
radially spaced apart concentric indicator lines for monitoring the
separation of the components. When the base and cover are superimposed,
the first and second channels define an annular interior chamber having
an off-centered figure eight configuration. The base and cover each
comprise a grooved column axially centered and extending from the base
top surface and the cover bottom surface, respectively. The flexible bag
comprises inner and outer tubes extending from the core of the bag and
which are seated in the column grooves to ensure that the bag is fixably
rotatable with the rotor.