Cryo tubes can be welded in with CryoFlex™ tubing. Therefore they can be stored in liquid nitrogen without penetrating nitrogen into the vials and building up pressure, which can cause the tubes to burst.
POA means "Price On Application". Items displaying POA instead of the sell price do so for a number of reasons, not least because we anticipate some additional information is required in order to supply the most suitable options/configuration to each individual customer.