Holds one 10-mm, 12-mm or 13-mm test tube rack. The Biomek Labware Holders allow placement of pipette tip racks, multiwell plates, reservoir holders, 24-place tube racks and test tube racks on the Biomek 2000 worksurface. The labware and pipette tip rack holders use single worksurface positions, and the test tube rack holders require two worksurface positions. High-capacity Test Tube Racks hold glass, polystyrene and polypropylene tubes up to 100mm in length.