This line of plastic test tube racks are shipped flat in order to reduce shelf space and then simply snap together for use. The special design allows all samples to be incubated at the same temperature. These racks can be used in freezers without deforming or going brittle. They will not rot, rust or deform. Alphanumeric markings are molded into the racks to provide easy test tube identification. They are available in four colors for color coding test samples, or simply for aesthetics in the modern laboratory. They are stackable when empty.