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). A silicone washer between cap and vial ensures a positive leakproof seal at all temperatures. A 11/4 turn of the cap is sufficient to seal the vial. Closure and vials are both manufactured of polypropylene with the same coefficient of expansion, ensuring an equally secure seal both at room temperature and at low cryogenic temperatures. Tubes have a whitemarking area, can be color coded with a CAPINSERT (Series T312) and are compatible with most storage systems. Only he round bottom vials can be centrifuged, and up to 17,000g. Sterilized by gamma radiation and packaged in unique tamperproof,resealable,safety-lock bags of 100. Autoclavable. Case contains : 10 bags of 100 in each bag.