11. It's this vacuum flask assembly that keeps the contents insulated from the outside world. 12. Vacuum flasks are often used as insulated shipping containers.13. Production of customized vacuum flasks " termos " for the water and guampas is common. 14. You cannot make a vacuum flask out of ice. 15. Then they visited Qiqihar, ate in a local restaurant and received Chinese vacuum flasks as gifts. 16. Several technological applications, such as NMR and MRI machines, rely on the use of double vacuum flasks . 17. Then, ice cubes and / or herbs are added to the water on to the vacuum flask . 18. In a vacuum flask they use a reflective material to reflect radiated heat back into the flask. 19. It was named for its superficial appearance to a Thermos bottle, a popular brand of vacuum flask . 20. Hence it is usually assembled into a vessel, similar in construction to a vacuum flask or Dewar.