Leather Armour of Pocketing (5e Equipment)
From D&D Wiki
Armor (Leather), uncommon
While wearing this armour, you can use an action to put anything into the armour's pockets, so long as the object fits into a five-foot cube. You can also use an action to retrieve an object from the pockets. When you are about to put something into the armour's pocket, or take something out, it morphs so that the pocket appears and then disappears after the object is put into the armour or taken out.
The armour can hold 500 pounds, not exceeding a space of 64 cubic feet. The armour weighs 10 pounds, regardless of its contents. If the armour is placed into an extradimensional space formed by a bag of holding, a portable hole, or a similar item (or if one of those items is placed inside the Armour of Pocketing), both items are instantly destroyed and gateway to the Astral Plane is opened. The gate originates where the one item was placed inside the other. Any creature within 10 feet of the gate is sucked through to a random location on the astral plane. The gate then closes. The gate is one-way only and can't be reopened.