Arcane Lock Box (5e Equipment)
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Wondrous Item, uncommon (requires attunement by a wizard, sorcerer or warlock)
This small chest weighs 10 lbs. and is made entirely of brass or iron. The box holds 3 cubic feet or 75 lbs. of items, and objects within are considered to be under the effects of a nondetection spell. Only the creature attuned to the box can open it freely. It has no keyhole, handle, or outside mechanism, making all standard non-magical means of opening it (like lock-picking) impossible. It can be broken open with a Strength check of DC 25.
The arcane lock spell can be cast upon the box as a ritual. If the alarm spell is cast upon the box as a ritual, its duration is twice as long.
If a knock spell is cast upon the box, the caster must make a DC 15 (or DC 20 if the box is secured with arcane lock) ability check using their spellcasting ability. If the check fails, the spell does not open the box.
If a dispel magic spell is cast upon the box, the spells affecting the box are considered to be 5th level.
If a creature attuned to the box is more than 100 feet away from it, they do not loose their attunement until 1 week has passed (rather than 24 hours).