Dimensional bag

The container used in the casting of the spell is moved into the ethereal plane. A small invisible opening is created leading to the main access of the container (the top flap of a backpack, the opening of a chest, ...). The invisible opening has the same dimension as the access to the container it is connected to. This connection follows the person currently in possesion of the glass replica used in the casting of this spell.

The spell ends when you cast this spell again using a different container, the glass replica is destroyed, or the container in the ethereal plane takes any damage. The spell also ends after 30 days. When the spell ends, the container returns to the casters plane, appearing in an unoccupied space next to the caster.

When you cast this spell on the same container again before the 30 days are up the time is refreshed.

If you cast this spell on the same object every 30 days for a year, without the container leaving the ethereal plane it becomes permanent and you can cast this spell again on another container without ending the spell on the first one. You can enchant a maximum of 3 containers in this way.

At higher Levels
If you cast the spell at 5th level or higher, you can either choose a container of a size up to huge, or choose a magical container such as a bag of holding.