Cryogenic Vial are manufactured from high-quality virgin polypropylene for store cells, tissues, microbiological samples, nucleic acid and protein samples in extreme temperatures ranging from -196 to +121°C, but should be used only in the gas phase of liquid nitrogen. Closures and tubes are made of polypropylene with the same coefficient of expansion, which further enhances the leakproof qualities of these vials at various temperatures.