Assassin's ring

A thin silver band inscribed with the words: 'I've got nothing to hide' in common.

While wearing the ring and being attuned with it, the wearer can use a bonus action to teleport one held item to a pocket dimension with maximum dimensions of one cubic foot. The item can be brought back with a bonus action. The ring itself turns invisible while an item is in the pocket dimension. 

Notes: The item transported to the pocket dimension has to consist of one whole, but could also encompass e.g. a closed bag with contents or a loaded handcrossbow. When another item that contains a pocket dimension or means of planar travel is teleported to the ring's pocket dimension, the ring and all items that it teleported disappear forever. Additional effects are up to the DM's discretion.