A small cube of ceraplast attached to an electronic keycard. When a type A power cell is inserted, the portabox immediately unfolds into a rigid locker with 1.5 x 1 x 1 meter dimensions.
The portabox is air-tight and has a simple electronic lock which can only be opened with the keycard or a successful difficulty 8 Sneak or Fix skill check. Failing the check will cause the lock to short-circuit and seal the box until it can be cut open with a metatool or broken open with twenty points of damage.