It's not enclosed in the final product. It is used during manufacturing. For example, you mechanically compress helium to get liquid helium, then when it depr

It's not enclosed in the final product. It is used during manufacturing. For example, you mechanically compress helium to get liquid helium, then when it depressurizes back to ambient pressure, it's -269 C, which is pretty close to "as cold as possible", and colder than any alternatives.