There is no distinguishing feature that would reveal the true nature of this backpack. It appears to be a well-made and well-worn backpack that could be found in every shop and worn by every traveller.
Illusions have been bound into the backpack that allow the bearer to hide its contents. When placing an item in the bag, speaking the command word causes the item to disappear. Anyone other than the person who spoke the command word who looks into the bag will not see the item, and if they reach into the bag, they will not feel it. The pack’s weight is also not changed by the weight of the item. The capacity of the backpack is the same as a regular backpack, and if the bearer attempts to put an item into the backpack when it is full, it will not fit, even if all the items placed previously have been obfuscated. Similarly, placing unnaturally heavy items can cause the pack to tear or break, just like a regular backpack. Discovering the command word requires an Arcana check (DC 15). A successful Arcana check also reveals that speaking the command word backwards reveals all items hidden in the pack.
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