CryoFlex™ - Hollow PE Tubing for CryoTubes

Hollow Polyethylene (PE) tubing
One CryoFlex Length: 500mm long, 14mm diameter
20 x 15 Lengths/case
CryoFlex™ Tubing
This heat shrinkable tubing secures CryoTubes (internal threaded style only) when they are immersed in liquid nitrogen. Heat and crimp to seal the top and bottom prior to liquid nitrogen storage.

20 packs of 15 lengths/case
(Note: One length of CryoFlex Tubing is 500mm long and 14mm in diameter)

One Length seals:
Seals approximately 120 x 1.2ml (1.0ml) size Internal Threaded CryoTube Vials (Cat. #CG7224) 41mm L
Seals approximately 100 x 2.0ml (1.8ml) size Internal Threaded CryoTube Vials (Cat. #CG7267) 48mm L
Seals approximately  75 x 4.0ml (3.6ml) size Internal Threaded CryoTube Vials (Cat. #CG9189) 72mm L
Seals approximately  65 x 5.0ml (4.5ml) size Internal Threaded CyroTube Vials (Cat. #CG9146) 90mm L  

(Note: CryoTube Vials are 12.5mm in diameter)

500mm/Length, tubing is 14mmØ (diameter)
15 Lengths/pack


1.) Can NUNC Brand CryoTube Vials be immersed in liquid nitrogen (liquid phase) for storage?

The CryoTube Vial of choice for liquid N2 immersion is the internally threaded design, incorporating a silicone gasket. At ultra low temperatures, any sealing material becomes inflexible. A theoretical risk of leakage is present when any mechanical closure is used. To facilitate leakproof storage, mechanically closed containers must be hermetically sealed in a protective envelope. The Nunc CryoSystem includes CryoFlex Tubing, a heat sealable polyethylene tubing designed for CryoTube Vial encasement. The use of CryoTube vials for freezing in liquid nitrogen (liquid phase) storage without CryoFlex Tubing poses a safety hazard.

Warning: Do not use NUNC CryoTube Vials in liquid phase of liquid nitrogen unless correctly sealed in NUNC CryoFlex Tubing, our #LS-2000 (or Nunc's #343958). Improper use may cause entrapment of liquefied nitrogen inside the vial and lead to pressure build-up, resulting in possible explosion or biohazard release. Use appropriate safety procedures as outlined in the Nalge Nunc International Cryopreservation Manual when handling and disposing of the vials.

2.) What is the protocol for thawing cells when CryoTub Vials are previously immersed in liquid nitrogen without CryoFlex Tubing?

Wear appropriate protective clothing including gloves, face guard, etc., during all transfer processes.

The CryoTube Vials should be stored at least 24 hours in the gas phase of the liquid nitrogen freezer. This should allow trapped liquid nitrogen to evaporate and escape slowly, thereby reducing the possible pressure in the CryoTube Vial. After at least 24 hour storage in the gas phase, the CryoTube Vials may be put into a water bath and covered with a towel. After thawing, tube contents can be transferred.

3.) Will the heat required to properly seal CryoFlex Tubing adversely affect my cells?

CryoTube Vials are normally placed in a 4°C ice bath during cell inoculation into the CryoTube Vial. The heat required to shrink the polyethylene CryoFlex Tubing will not raise the internal temperature enough to damage the cells. At this stage, cryoprotective agents are added.

  • Nunc CryoFlex™ provides extra safety when freezing hazardous samples or storing in liquid nitrogen.