Cryotube is made of Medical grade PP material, It is the ideal lab consumable for biological sample storage. In the gas situation of liquid nitrogen, it can withstand temperature as low as -196℃.Silicone gel O-ring in the cap ensures no leakage, even in the standard lowest storing temperature, which will guarantee the sample safety. Different inserted color top will help easy identification. White writing area and clear graduation make the mark and volume calibration more convenient.