Compared to Space Rings, Space Expansion Boxes have many disadvantages, such as not being portable enough, prone to structural damage, and poor concealment.
Because they are themselves Space Items, Space Expansion Boxes cannot be stored inside Space Rings or special Subspace like personal space.
However, it also has a significant advantage; since the base material is sufficiently large, the capacity of the Space Expansion Box can be much larger than that of Space Rings.
For instance, right now, the Expansion Box Anvis prepared looks similar to a wheeled suitcase, and its internal space reaches hundreds of cubic meters.
Actually, it was initially prepared for transporting items from the Secret Vault of the Ancient Magic Empire, but now it can be used in advance here.
