Cube modules are color coded for convenience. Rotate each cube independently-use several sizes of Test tubes, culture tubes, or Micro centrifuge tubes at the same time. Each system consists of four cubes and one support tray. Compatible with the following tubes: 15- and 50-ml Conical; 12 x 75 mm, 13 x 100 mm, 16 x 125 mm, and 17 x 100 mm culture; and 1.5- and 2.0-Ml Micro centrifuge. Autoclavable.