Made of polypropylene. Designed for storing biological material, human or animal cells, at temperatures as low as -196°C but should be used only in the gas phase of liquid nitrogen. The cap features a long skirt for one hand aseptic methods, a super fast thread design that allows tightening or removal with a mere 1 1/4 turn, and an inside thread design that will not contribute to possible contamination. Tubes are provided with a white marking area for sample identification.