IsoFreeze Microcentrifuge Tube Racks. enables you to see how cold your samples are at a glance. IsoFreeze® color change racks undergo a dramatic change to a contrasting color at 7ºC. Dimensions: 146 × 105 × 70 mm. Tube capacity: 24 x 0.5, 1.5, 2.0 mL snap or screw-cap style tubes. Rack comes with lid.