Similar to the Item Box's ability, it is considered as a storage box used to store objects.
As the name suggested, this magic item looks to be in the shape of a box. In the anime, it was displayed to have intricate patterns on all sides of the box.
If someone tried to forcefully open the box, it would trigger an extensive array of attack spells. The kind wherein all of which would be centered on the box to destroy it. Unless it was someone level 90 with a rogue class job or a character over level 80 with full specialization as a rogue, it was near impossible to open it.
- Ainz has sealed away the Memo Pad inside this magic item as protection.