Cryo-caskets are devices used to store people in cryonic sleep. Caskets are intended for long term use and can keep patients inside for decades. They are capable of being used on board ships.
Cryo-caskets are primarily intended for the continued preservation of cryonically frozen patients, not their initial freezing or eventual revival. They possess limited systems that can aid in these processes in the event of emergency, though this is not recommended, as it can cause serious complications.
The caskets typically work by using liquid nitrogen to keep tissues at around 77 K. The caskets are highly efficient and need very little in the way of replacement nitrogen. More advanced caskets are capable of recooling the nitrogen through the throttling process, meaning they can act independently for decades without maintenance.
Cryo-caskets have been around almost as long as cryonics has been a viable method of preserving individuals. In the early days of cryonics, patients needed to be kept in massive facilities specially designed for their continued preservation. Transportation of individuals was complicated, dangerous, and messy.
Once the science of cryonics became well-developed, cryo-caskets were a rather simplistic invention. Because cryonics was originally used mainly in the preservation of terminal individuals for eventual revival and treatment, the devices were termed "caskets". Even once cryonics advanced to the degree that it was used on healthy individuals on "sleeper ships" or the like, the term remains.