Designed for safe storage at temperatures as low as -196 °C (but should be used only in the gas phase of liquid nitrogen). Autoclavable at 121°C. Sterilized by gamma radiation and packaged in unique tamperproof, resealable, safety-lock bags of 100. Skirted tubes have a locking base for easy one-hand operations and only 1 1/4 turn of the cap is sufficient to screw the cap on the vial. Closure and vial are both made of polypropylene having the same coefficient of expansion, ensuring an equally secure seal both at room temperature and at low cryogenic temperatures. Tubes have a white marking area, they can be color coded with a Capinsert™ (Series T312) and are compatible with most storage systems. Only the non-skirted vials can be centrifuged up to 17,000 x g.