Cryo tubes are used to store samples in freezers or similar low-temperature equipment. When stored in the gas phase above liquid nitrogen at -196 °C, stress is generated in the tubes. Appropriate design and a high-grade polypropylene material ensure safe handling during and after the unfreezing. With the geometry of the external thread on the tube, a silicone gasket on the lid becomes unnecessary. The gastightness is guaranteed at all times.